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Red Running Blue


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Checked the fuel pressure regulator today. When it read 1.5 bar (supposed to be 2.4 - 2.6) I thought, ah ha. Then when the fuel pressure gauge jumped to over 7 bar when I blipped the throttle and stayed there I thought, ah ha ah ha. So Bosch number (it's in the book) for $150 produced NOTHING DIFFERENT. Put the fuel pressure gauge back on an it still read 1.5 but did not go up no matter what I did with the throttle. CO was about .13 at idle but it went total fat 1.75 at 2000 rpm. O2 Sensor does sweep (all at less than a volt). The gauge is a Peugeot factory unit. Being off by 1 bar on a gauge that only reads up to 6 is rather dramatic but I assume the regulator is close as the high CO off idle indicated rich. Anyway after that I looked at the timing ........... the book shows 2 marks. the first one (called #2, go figure) looks like this ( I ) the second looks like this ( II ) yet there appears to be a third one that looks like this ( II ). The engine died way before I could get it to ( I ) so it is now sitting on ( II ).

It runs better than it has in quite a while floored but off idle it hunts and surges and pings before it gets to full boost. Inasmuch as timing is the first thing that has had a direct effect on the issues, I'm thinking distributor and I have a spare (but wonder why it is a spare) so I will put that one . However I need to resolve the timing marks issue.

btw: The AFM still reads 10.5 volts (should be 7.2) with the screw all the way in and the throttle by-pass is as far out as is practical. The idle is now 875 (hot)

All thoughts will be considered as I still feel lost. :blink:

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Gauge error would explain it - but it'd be nice to know for sure what the FPR is set at.

As for timing - whenever I suspect that the timing has been messed with I always bring the #1 piston to TDC on compression stroke (Air comes out of the plug hole on the way up), and then I verify that when it's at TDC the crank is at 0 which will also confirm which mark on the crank, and the rotor in the cap is pointing at #1 plug wire.

Then time it to 10 degrees and see what it does.

Sounds like you could still have a vacuum leak as I've found advancing timing will help an engine cope better, but it still runs like crap under load. When hunting vacuum leaks I'll often disconnect and plug vacuum ports at the engine one at a time to eliminate all the vacuum line circuits. If one of them makes a difference - I then trace it and verify all is OK.

Was the cat ruled out?

Rabin

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OK, did the timing by piston TDC and while the book shows two timing marks on the pulley Red has three (whatever) suffice to say that the timing is correct. The TPS is correct. The AFM volts are off. Interesting that after retiming the car runs worse than it did before. Meaning the surging and bucking before would subside after 3000 rpm but after the surging would not quit until after 4000 rpm. I could video what the engine is doing as it can be replicated just slightly off closed throttle. I guess doing the Pin-out box needs to be done to check the volts at the ECU (maybe a mouse ate the wiring affecting the TPS?)

Trying to get my head around the converter question as I would assume any issue with the converter would be progressive as the volume of exhaust increased but Red runs very well accelerating or floored. It's light throttle cruising it can't do.

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Trying to get my head around the converter question as I would assume any issue with the converter would be progressive as the volume of exhaust increased but Red runs very well accelerating or floored. It's light throttle cruising it can't do.

That does rule the cat out, since it wouldn't let it breathe up high at all. The scenario you mention above of it being OK on acceleration / WOT is classic vacuum leak symptoms.

I'd plug ALL the vacuum ports off the intake, then see what it does. More to rule it out than anything else. Do you have a vacuum gauge to see how stable it is while it's acting up?

Rabin

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Ya I have (and it's been there since we raced Red) a vacuum/boost gauge T'd into one of the ports on the intake manifold. Vacuum is steady at near 20 at idle & boost is steady at 9.5. When replacing the FPR the vacuum hose was cracking at the FPR but fixing that didn't change anything. I used propane and never got any responses. This all goes back to my original quirry: How can you have a vacuum leak and still show high vacuum at the intake manifold. We decided that the AFM boot had to be the culprit as it could leak there, being un-metered air, and still show high vacuum but the boot had no effect (looks nicer tho, thank you). Got a AFM?

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Not a new AFM... I have a few used ones. Wouldn't Deuce's AFM swap in as a test?

And BIG vacuum leaks should show up on the vacuum gauge, but an unmetered air leak prior to the TB wouldn't necessarily be a "vacuum" leak, but it would have a similar effect.

For giggles try unplugging the O2 sensor and see what happens.

Rabin

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I am reluctant to disturb things and would rather not take it out of Deuce but I suppose that wouldn't be so terribly invasive. <_<

If there were a "vacuum leak" after the turbo wouldn't it loose boost? I remember one race at Riverside where the turbo housing cracked and it sounded very odd and was low on boost. Jus sayin'

I unplug the o2 but I don't think the o2 works as fast as the surges occur. I will also do some voltage and resistance tests to the AFM as outlined in the book.

Thanks for your input too. :D

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While you're at removing Deuce's AFM - :) - I'd make it a point to rehab all the connections with electrical cleaner, small brush, and some dielectric grease. Giving the grounding points the same cleaning / dielectric treatment, as well as ALL electrical sensors and their harness connections on the engine.

When it gets really disturbingly erratic and everything checks out - I usually assume it's electrical with Peugeot's oh so nice unsealed electrical connections, and exposed grounding trees. All sorts of wackiness can happen with bad grounds.

Rabin

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  • 2 weeks later...

Update:

Used the factory "Pin-out" box and got bizarre results so I'll go after the grounds. AFM was supposed to be >12v on one test and it read 1v (which is certainly less than 12) and another test where it was supposed to read 1 - 2v and it read 8.75v. However, inasmuch as Red has thrown two codes (5 and 6, which both relate to the TPS) I'd predict there is an issue there as well (I don't have the book in front of me so I don't remember what the reading were for the TPS).

Anyway, There is a ground tree on the radiator core support (under air box). Are there others I should find??

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There's one on each side of the radiator, but I'd also suggest doing the block ground, chassis ground, and ensuring the battery cables are nice and clean at the battery, alternator, and starter for good measure. They can look great - but pulling them apart and cleaning them up can still make a big difference.

BTW - If you google AFM rebuild the Porsche guys have lot of info on fixing them - and it seems dead simple to do.

Rabin

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I swapped AFM and the readings were identical. Today the ground at the driver right was serviced. Next will be the rest of the grounds but that TPS thing needs to be resolved.

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  • 3 weeks later...

RED HOT RED

We're baaaaaaaaaaack.

I gave Red to Dubarr Automotive in Huntington Beach, a long time Peugeot shop and he came back and said ................. intake manifold gasket. I said how can you have a intake manifold gasket failed and 18" of vacuum and correct boost? I told him I was betting against him but go ahead.

He called said it was ready. I walked up to Red, started the engine and it had 18" of vacuum. I drove it and it had correct boost but it is fixed.

I don't get it. He didn't do the pin-out box so I have to assume the Red has alien electrons.

Red has had three failures in his 200,000 miles. Intake manifold gaskets twice (apparently) and one cracked turbo housing (hot side)

God it's good to have him back. I think I'll go chase down a Mustang or two.

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I really don't like this. Don't get me wrong I'm happy Red's feeling better but take a look at the intake gasket (ya it's ripped up some) with a magnifying glass and tell me where it's failed (all tears are from removal)

post-137-0-56786900-1340234102_thumb.jpg

post-137-0-38579800-1340234122_thumb.jpg

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Stumped me on why it ran rough - but the only reason for the intake to be the cause and still be intact is that it was loose IMHO... Only other thing I can venture to say is that maybe the leak was only so minor as to only affect idle quality and not big enough to actually change the vacuum reading (or noticed on the gauge at least) - or affect the boost (again by an amount that could be seen on the gauge...)

Glad it's fixed of course - but I totally agree with you on not being very satisfied with the "solution".

Rabin

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