Red Running Blue

[SSB]

Red's not running very well recently. I've been poking around and suspect a vacuum leak except the boost/vacuum gauge (not factory) says 18lbs steady and 9.5 lbs boost. Anyway, I throw it to you guys as here is what I've done so far. I'm looking for new suggestions or someone who recognizes the symtoms.

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Condition;

Stumble off idle. Hesitates on light throttle. Hesitates on full throttle. No codes

Actions;

Changed TPS (throttle position switch) and ran much better coming home except light throttle hesitation and stumbling. Went to check air flow meter (possible lean off idle?) prepared engine for test and got code 6 instead. Code 6 is no signal between ECU and TPS. Permanant fault means have to turn off and restart to clear code. Code cleared after many trys. Preceed with air flow meter teest. Should read 7 ( -2) read 9.5. To reduce volts turn screw in (already all the way in). Road test car. Runs now like it did before TPS was changed.

Assumptions:

Used Factory Peugeot TPS/Micro switch test box to see if wiring issue was from TPS connector to TPS. Inasmuch as it read correctly I assume the wiring is ok.

I turned Air Flow Meter screw out and volts went up higher

I pushed the vane (inside Air Flow Meter) volts went down

Vacuum is 18lbs assumes no intake leak however carb cleaner around throttle caused momentary fall in idle. Replace O-Ring at throttle body. No change

Test drove car - poor performance/stumbles ant high and low RPM with uneven idle

Inside the airfilter box, there is a tube (intake horn, if you will) before the airflow meter. I placed my hand over the tube completely and there was very little vacuum and kept idling like before. Did the same thing to Deuce which had a much higher vacuum and while the idle dropped a couple of hundred RPM, it too kept running.

Red shows about 18lbs of vacuum. Is it supposed to have more? I can't find anything about vacuum in the book.

I have sprayed Carb Cleaner through the engine bay and get no response however inasmuch as the voltage is reading over 9 volts at the airflow meter (supposed to be 7.2 -.2) and the volts go down when the vane responds to higher RPM wouldn't that say the air is coming in from somewhere else. If all the air were coming past the airflow meter then the vane would be open further and the volts would be less.

Deuce's airflow meter volts is 7.2 to 7.8

Reds idle mixture screw is all the way in (turning it out makes the volts go higher)

I'm lost

[Bean]

Is the AFM to turbo intake boot in good condition? Have you checked timing? Distributor cap / rotor / plugs / plug wires?

If you can also check ignition advances when revved - that would be good to rule out. Did you have any trouble setting up the TPS with it's intricate procedure for setting it up? tps adjustment procedure

I've had similar symptoms and the timing had gotten a bit advanced and it was running terrible. Reset to 10 degrees and all was good.

I would guess your car not stalling out when covering the AFM is a bad thing. It should be the only way for your car to get air, and covering it should stall the car out. I wouldn't use my hand however - but piece of plexi or something that's strong and has a better seal. I'd then use a propane bottle to search for anywhere that could be sucking in air - if idle raises with the propane you found your leak. Since your engine vacuum is steady - I'd suspect connections up to your throttle body.

Rabin

[N9TE]

I'm not liking the 9v at the air meter. Ever thought of temporary swapping Deuce's AFM over to Red to confirm/dispell the voltage variance factor?

Upsides: free and will get a better look at AFM hose.

Downside: kindda a PITA

[JunktionFET]

Are you reading the 9v at the AFR test wire? If so, that indicates a pretty lean condition, so like the others I'd suspect anything from the air flow meter to the throttle body. Since you idle vacuum is pretty-alright, it might be safe to assume that everything from the throttle body to the intake valves is sealed up tight.

I'd check this:

- The "Accordion" hose from the air flow meter to turbo; Check for tears/splits

- All three silicone o-rings between the turbo, intercooler, and throttle body

- The PCV system--the big fat hose that runs from the "Accordion" hose to the valve cover; Check for tears/splits

[SSB]

Boot OK (sort of) old and the (what's that hose that comes into the top, anyway) comes off rather easy. Sprayed Carb Cleaner and didn't get any response. What are we doing for AFM boots these days anyway? Making August Boots?

I have the factory "Box" for setting the TPS and it's set right (tho I'm bummed about that code 6 (no signal to ECU from TPS but it went away)

If the acceleration were steady and poor I'd think timing but it's hesitating. Could that be timing?

I put my hand over Deuces Air Horn and it had allot more vacuum but still I could cover it and loose 400 RPM but it would keep running (not much need for plastic). The Vacuum gage is connected right to the intake manifold and reads 18 LBS. Should it make more vacuum? But I'll try propane.

[SSB]

Ya the volts go down as the air flow increases. Right now the "idle mixture screw is all the way in (meaning if I run the screw out the volts go higher). That should say that there is a vacuum leak and my covering the inlet and it keeps running would assure us that there is a vacumm leak - except the vacuum gauge reads 18 LBS. I could/probably will swap AFM's

I'm not liking the 9v at the air meter. Ever thought of temporary swapping Deuce's AFM over to Red to confirm/dispell the voltage variance factor?

Upsides: free and will get a better look at AFM hose.

Downside: kindda a PITA

[SSB]

Ya using the connector between the fender and the air box and doing the set up as outlined (PVC hose plugged and 60 degree by-passed) Lets see now, the volts go down as the vane opens so ya if the volts are higher than it would be leaner. The idle mixture screw by the way is all the way in and even the throttle by-pass screw is nearly all the way in. All this points to vacuum leak but (and sorry if I keep going back to this) but how/why would it show 18 lbs vacuum and 9.5 lbs boost (have had gauge on there for many years)

I haven't taken the Boot out as it's old and probably grumpy about being disturbed but I did spray carb cleaner all about and got no response (I know boot doesn't like carb spray either) so I'll try propane. The PVC hose (which is asked to be plugged during the AFM test as well as the 60 degree sensor) is good at both ends but I haven't seen it behind the engine, but could you still have 18 lbs of vacuum if the PVC hose were open? O-rings have all been looked at and renewed (had some in house, actually)

Are you reading the 9v at the AFR test wire? If so, that indicates a pretty lean condition, so like the others I'd suspect anything from the air flow meter to the throttle body. Since you idle vacuum is pretty-alright, it might be safe to assume that everything from the throttle body to the intake valves is sealed up tight.

I'd check this:

- The "Accordion" hose from the air flow meter to turbo; Check for tears/splits

- All three silicone o-rings between the turbo, intercooler, and throttle body

- The PCV system--the big fat hose that runs from the "Accordion" hose to the valve cover; Check for tears/splits

[Bean]

All this points to vacuum leak but (and sorry if I keep going back to this) but how/why would it show 18 lbs vacuum and 9.5 lbs boost (have had gauge on there for many years)

I haven't taken the Boot out as it's old and probably grumpy about being disturbed but I did spray carb cleaner all about and got no response (I know boot doesn't like carb spray either) so I'll try propane. The PVC hose (which is asked to be plugged during the AFM test as well as the 60 degree sensor) is good at both ends but I haven't seen it behind the engine, but could you still have 18 lbs of vacuum if the PVC hose were open? O-rings have all been looked at and renewed (had some in house, actually)

You can have no vacuum leaks between the throttle body and the head which would show steady vacuum readings, but have air leaks between the AFM and the throttle body. This is letting in un-metered air and can cause all sorts of running issues like lean since the AFM is measuring a fraction of the air being used.

I'd seal the AFM off and look for air leaks again. Engine is consuming 1077.5 cc of air every rotation so that's a crap load of air getting by the AFM. The lean condition, and the fact it's running with the AFM covered narrows it down pretty good.

As for the intake boot - I've got a NOS OEM boot, and I think Nick Cota has one as well in the for sale section. Alternate is a custom set up like August did up on my 89.

Rabin

[SSB]

That's what I was looking for. An explanation for why the vacuum read good but that Red acted like a vacuum leak. How does the PVC hose (and the dip stick for that matter) figure into the leak? Between the AFM and the throttle, right? OK, who do I buy the boot from?

You can have no vacuum leaks between the throttle body and the head which would show steady vacuum readings, but have air leaks between the AFM and the throttle body. This is letting in un-metered air and can cause all sorts of running issues like lean since the AFM is measuring a fraction of the air being used.

I'd seal the AFM off and look for air leaks again. Engine is consuming 1077.5 cc of air every rotation so that's a crap load of air getting by the AFM. The lean condition, and the fact it's running with the AFM covered narrows it down pretty good.

As for the intake boot - I've got a NOS OEM boot, and I think Nick Cota has one as well in the for sale section. Alternate is a custom set up like August did up on my 89.

Rabin

[JunktionFET]

Forgot to add: Also check the auxiliary air device plumbing--the rubber hose that connects it to the curved intake pipe off the intercooler.

[SSB]

I know the hose to the throttle is good but behind that, I know it's connected to the aux air device so I need to look at the other end, right?

Forgot to add: Also check the auxiliary air device plumbing--the rubber hose that connects it to the curved intake pipe off the intercooler.

[JunktionFET]

The other end of the aux air device (the hose that leads under the intake manifold) connects to the cold start injector's little "sub manifold", and is subject to manifold vacuum. So if any of that was leaking, you'd have weak vacuum potentially. Still might be worth a check though just in case. And check the brake booster hose while you're in there--it attaches to the same stuff. I'm assuming this is a non-ABS car... The ABS cars obviously don't have the vacuum brake booster, but instead have a potentially problematic vacuum cap where the hose would have gone.

[N9TE]

The AAD probably isn't your problem. It allows extra unmetered air on startup/warmup. When warm, pinch the hose closed. The closer to the intake pipe in front, the better. That way you're checking not only the AAD hose, but the AAD itself. The engine speed should not drop. If it does, it (or it's hoses) are letting in air outside of it's role.

Conversely, pinching it after startup should induce a small drop in RPM at idle.

On most cars LU-Jet cars, the AAR is barely operable and not a big deal. Same goes for the Startup injector/thermotime switch.

That 9V from "wire 4" needs to be addressed. The ECU thinks it is running rich. Either:

a. You have a false air source

b. Lambda suddenly went TU

c. AFM suddenly went TU

[JunktionFET]

^9 volts from the test wire is a lean condition, not a rich condition (0 to 7 = rich, 7 to B+ = lean).

[Bean]

The AAD probably isn't your problem. It allows extra unmetered air on startup/warmup. When warm, pinch the hose closed. The closer to the intake pipe in front, the better. That way you're checking not only the AAD hose, but the AAD itself. The engine speed should not drop. If it does, it (or it's hoses) are letting in air outside of it's role.

Just to clarify - the AAD only route's air around the throttle plate, but it's still coming through the filter and AFM so it is metered.

Definitely curious to hear what you find - but I'm guessing AFM to turbo is split.

Rabin

[SSB]

I really like the dialog we've had here, very collected and insightful. Fun even. So I need to know if Beans boot is correct for Red and I will buy it (assuming it is still available) an after that I can switch AFM's and propane everything between the AFM and the throttle. We agree?

[N9TE]

Rabin's AFM hose is correct. However, I'm sure he doesn't want to sell you something you don't need. Disconnecting it is a bit of a pain, but not too much so. The upside to owning a good spare is the hose does wear out. And it will work on both Red or Deuce if either one of them fails.

Usually, you can't tell, but looking at it or giving it a cursory in situ feel up. It's usually way too filthy and it's according pleats make it easy to conceal leaks.

Pulling it will allow you to clean it properly off-car. If it's good, then you can just pull the AFM from deuce and put it on Red and see if that fixes your problem.

Clean everything well, but I shy away from really cleaning the AFM. Although they aren't as fragile as the hot-wire setup on ZN3J or the Motronic, it's still fragile enough for people to have rendered them inop after dousing them with carb cleaner or whatnot.

Did any "event" precede the poor drivability? Like a full throttle run? Full throttle runs can cause the engine to pull to one side causing the AFM hose to be stretched. (That's one reason they fail)

[SSB]

Ya I've gone ahead and bought the Boot. Spares are good things (especially NOS)

It was quite awhile ago that these symptoms started but Red's in Semi Retirement now anyway so not first priority. This next story is going to sound bizarre and I'm embarrassed that I never though to look more often under the hood. A few months ago, Deuce started to idle rough. Ran ok but sounded embarrassing. Then Red starts to run the same way. The only event that occurred at the same time was Smog Checking them at a "Check Only station" (Not allowed to repair, it's a California thing). This was done at the shop next door to my maintenance/repair shop Westside Motors. I've been told by "mechanics" that compression should be checked first but why would both cars do the same thing at the same time so that was the last thing I did (leakdown and compression are good). Checked Deuce for air leaks, checked fuel pressure, checked ECU, changed spark plugs, checked plug wires, even replaced the injectors (Anybody want to buys a set of used injectors? Apparently they are good). No change. Then I went to look at the AFM. Surprise, the air filter was gone. Guess it just rotted away as it was the original filter (26 years old) Didn't have a boroscope and wasn't sure I wanted to use heavy cleaner on the intake side as it could dislodge the burnt plastic mountain that I imagined existed on top of the intake valves. Eventually the engine ran better and I did use a product called Sea Foam and had it sucked into the intake manifold. The issue subsided almost completely. To the point where I doubt anybody would notice but me. Now I go after Red. You think I'd look at the air filter first? Nope. Went down the same road except Red had this uneveness about it. So eventually I looked in the airbox and "surprise, surprise" the air filter was also gone. The rest of it, as they say, is history. :blink:

Rabin's AFM hose is correct. However, I'm sure he doesn't want to sell you something you don't need. Disconnecting it is a bit of a pain, but not too much so. The upside to owning a good spare is the hose does wear out. And it will work on both Red or Deuce if either one of them fails.

Usually, you can't tell, but looking at it or giving it a cursory in situ feel up. It's usually way too filthy and it's according pleats make it easy to conceal leaks.

Pulling it will allow you to clean it properly off-car. If it's good, then you can just pull the AFM from deuce and put it on Red and see if that fixes your problem.

Clean everything well, but I shy away from really cleaning the AFM. Although they aren't as fragile as the hot-wire setup on ZN3J or the Motronic, it's still fragile enough for people to have rendered them inop after dousing them with carb cleaner or whatnot.

Did any "event" precede the poor drivability? Like a full throttle run? Full throttle runs can cause the engine to pull to one side causing the AFM hose to be stretched. (That's one reason they fail)

[Bean]

If you get that AFM hose off - I'd take a look at your turbo blades as that air filter would have had to go through the turbo. It's just foam - but the turbo can spin up to 100000 rpm and any damage to the tips or fins will affect it's efficiency and possibly balance.

It'd also have to get through the IC, so I'd check and clean that out, and all the pipes from air cleaner to throttle body for any foam residue.

Rabin

[SSB]

To be sure, however Red didn't seam to be bothered as much by the indigestion (bon appétit mon ami) as Deuce. I wonder what the catalytic converted thought of the fare?

If you get that AFM hose off - I'd take a look at your turbo blades as that air filter would have had to go through the turbo. It's just foam - but the turbo can spin up to 100000 rpm and any damage to the tips or fins will affect it's efficiency and possibly balance.

It'd also have to get through the IC, so I'd check and clean that out, and all the pipes from air cleaner to throttle body for any foam residue.

Rabin

[tulaweb]

This next story is going to sound bizarre and I'm embarrassed that I never though to look more often under the hood. A few months ago, Deuce started to idle rough. Ran ok but sounded embarrassing. Then Red starts to run the same way. The only event that occurred at the same time was Smog Checking them at a "Check Only station" (Not allowed to repair, it's a California thing). This was done at the shop next door to my maintenance/repair shop Westside Motors. I've been told by "mechanics" that compression should be checked first but why would both cars do the same thing at the same time so that was the last thing I did (leakdown and compression are good). Checked Deuce for air leaks, checked fuel pressure, checked ECU, changed spark plugs, checked plug wires, even replaced the injectors (Anybody want to buys a set of used injectors? Apparently they are good). No change. Then I went to look at the AFM. Surprise, the air filter was gone. Guess it just rotted away as it was the original filter (26 years old) Didn't have a boroscope and wasn't sure I wanted to use heavy cleaner on the intake side as it could dislodge the burnt plastic mountain that I imagined existed on top of the intake valves. Eventually the engine ran better and I did use a product called Sea Foam and had it sucked into the intake manifold. The issue subsided almost completely. To the point where I doubt anybody would notice but me. Now I go after Red. You think I'd look at the air filter first? Nope. Went down the same road except Red had this uneveness about it. So eventually I looked in the airbox and "surprise, surprise" the air filter was also gone. The rest of it, as they say, is history. :blink:

That does sound familiar. My 505 was not in regular use for about 5 years. I occasionally drove it around the block a few times to keep the moving parts moving. A few months ago I started preparing it to go back to being my daily driver. Step one was to change the fuel filter and the oil and oil filter. I went on to project after project and only maybe 1,000 miles later I got around to the air filter. When I opened it up and the foam was all disintegrated into a gooey mess. I guess I was kind of thinking of the life of an air filter being based on the amount of air sucked through it, while putting old oil and fuel through their filters would make them need changing quickly. On the other hand maybe I just wasn't thinking.

[SSB]

Bummer. There were no issues for the AFM boot although I did replace it anyway as the old boot was BMW (part number 1726326). PCV hose was OK as well as EFE hose). Propaned about today and no response. Checked volts at AFM again and it was still 3 volts high with the by-pass screwed all the way in and the throttle by-pass all the way out. Still very weak (abet steady) idle. Stalls cold and sometimes hot. Check the pre-pump in the tank (early style) and the main pump and they are running. Car stumbles and hesitates and all acceleration modes. All that said the light throttle/off idle is better.

So I guess I need to see fuel pressure, o2 read-out and C/O.

Any thoughts???

[andrethx]

could it be something as simple as crappy gas? i've gotten several tanks of bad gas in my VW lately, from different local places (including places that one would think would have no quality problems). i sincerely believe that the quality of gas we get here in LA is deteriorating.

...hard starting, runs crappy...a fill up from somewhere else, along with some nice additive always fixes the problem (along with a mental note not to buy gas from that place anymore)...

andré

[SSB]

This has been going on for about a year but I don't drive Red all that often. The volts being off at the AFM is the tell but the cause isn't necessarily the AFM (at least until fuel pressure and o/2 signal is known). And I have Deuce is compare with. It's volts are correct and it runs very strong. But your right about the fuel except to me it only manifests itself in MPG.

[Bean]

This one is a stumper...

Plugged catalytic converter?

What happens if you unplug your O2 sensor? Any change?

Knowing fuel pressure is pretty much a must now as well to at least rule it out.

Keep us posted!

Rabin