konakat

I have not. I'll give that a go and see what I find.

konakat

Car was threatening to die again this morning so I pulled off the highway at the first available exit. Swapped the ignition coil in a parking lot but it didn't fix anything. Fuel pressure needle was again waving wildly between 20-30psi, so I have ordered a new damper and we'll see how that goes.

88Silver924S

If I understand it correctly the fuel pressure regulator "regulates" the maximum pressure such that when the pressure hits 2.5 bar (for my car) it opens and returns fuel to the gas tank to keep the pressure from getting excessive. On the other hand the damper is just a shock absorber that smooths out fuel pressure pulses. I don't understand how the vacuum connection functions. Both have a neoprene diaphragm inside I believe but I've never taken either one apart. If they are both the originals from 1984 it may be time to retire them even if they are not today's problem. How many miles on the car? Fuel pump wiring sound (good grounds at the pump)?

Your symptoms don't sound like a clogged fuel filter but just the same how old is the fuel filter? Have you inspected the spark plugs? One can read many things by looking at the firing insulator. This is just one site: http://www.ngksparkplugs.com/tech_su...d.asp?mode=nml do they look normal? I have heard some people have problems with non-traditional copper plugs like the platinum, etc plugs. That shouldn't cause your symptoms though.

Wish I could be more help. It will be interesting to learn what your problem actually is.

Jorgen944

This sounds strangely similar to an issue I had with an audi I used to have. Not sure on the systems here but it was actually a crank sensor that would heat in my case and cause the car to not know where it was and throw everything into a mess.

konakat

The fuel pressure never gets too high, just oscillates wildly. I probably should replace both, but for now I have the damper ordered and we'll see what happens there. I just changed the fuel filter a couple months ago and I have swapped the fuel pump with a used unit to see if that made a difference (nope). I also have replaced the reference and position sensors. I just brought the car home a little while ago and it is running worse than ever before. Felt like it might be running on 3 cylinders a lot of the time, but sometimes it would smooth out like it was running on all 4 for a couple seconds. The plugs are black, indicating I am running rich, but I already knew that given how bad the exhaust smells. I idled the car in a dark garage and saw some very faint arcing from two of the plug wires when I rev'd the engine. Is any arcing at all acceptable? I also looked at the cap and rotor, but didn't see anything suspect, though I have no idea how to identify a bad cap and rotor. The cap, rotor, wires, and coil all look like they must have been replaced shortly before I bought the car 8 months ago, very clean. Maybe the previous owner was chasing this issue and couldn't figure it out so they dumped it on me?

So my plan going forward is this, please chime in with any input.

1. Replace damper. If fuel pressure still oscillates, replace FPR also.
2. Cry

mel_t_vin

When you replaced the filter, did you R&R the in-tank screen/strainer, as well?


Possibly indicative of a faulty FPR or O2 sensor. Did you ever pull the vac lines off the FPR/FPD? Any fuel smell at line/nipple?


No. R&R with quality wires. Any markings on your wires?


IIRC, the cap/rotor are on a 30k service...and not that expensive. Probably couldn't tell if a cap had 5k or 50k on it...very easy to wipe down the outside. Any paperwork to verify your suspicion that they were recently replaced?

konakat

I did not do the screen because I was dumb and filled the tank shortly before replacing the filter. I'll add that to the list and do it once I've burned a bit more fuel. Skeptical that it is the problem since my fuel pressure seems to be high enough, just erratic.


The vac lines were dry. I'll try disconnecting the O2 and see what happens. I actually have a replacement but I haven't been able to remove the old one.


Not sure what you mean by markings. They are Nology Hotwires with a ground shield. It seems that they are somewhat controversial, but they look very new and are still very supple. The arcing is near the end where there is no shield.


No paperwork on this car at all. The inside of the engine bay was pretty filthy except for the ignition system, hence why I think they are pretty new. Even the inside of the cap is clean.

mel_t_vin

Probably not your root cause...just PM to avoid premature contamination of your filter.


Will help to apply Kroil/Wurth penetrant, repeatedly over a period of days, to break loose old O2 sensor.


By markings I meant manufacturer/brand labels. Sorry...no experience with Nology. Maybe others will comment.

Regardless, there should be no arcing. I would definitely replace these ASAP. As you are already running rich [black plugs, exhaust smell], a weak spark at the plug, due to excessive arcing, does not help a poorly running condition. So, to re-cap, fuel pressure spikes [damper] > chamber goes rich [black plugs] + weak spark [arcing] > engine stalls.


So, I only put OEM ignition parts on my car and my cap/rotor/wires are 10+ years old...no issues, to date.

Not sure if the OEM cap/rotor have Bosch markings or not [if I were near my car I would go look]. Have you looked at yours to ascertain manufacturer? As the PO installed aftermarket wires [Nology], there's a good chance he/she installed an aftermarket cap/rotor.

Anyone else care to comment on quality of aftermarket cap/rotor/wires?

konakat

Thanks for all your input, I really want to get to driving this car. Any advice on what wires to buy? I also just noticed that you are local. Were you selling a red n/a car last fall? I think I talked to someone from Silver Spring when I was car shopping.

mel_t_vin

My money is on your FPR/FPD.

Re: wires, I would put a set of used OEM wires [~$40] on before a set of new, aftermarket, knockoffs [~$100]. It's been a while since I looked, but, I think new OEM wires [Bosch with Beru connectors] are ~$140 [Paragon, Zims]. I wonder what OE wires would cost from Sunset?

Josh, got a decent set of [gently] used 8v wires laying around collecting dust?

Yeah, looks like I'm just down the road from you. No, that wasn't me selling a car last year. If you haven't gotten to the bottom of this by weekend after next [14/15 Jun], I'll grab a couple guys [and a 12-pack] and see if we can figure out what's ailing your ride.

konakat

I'll be out of town that weekend, but that would be awesome. I'm definitely not too proud to accept some help. I can even provide some homebrewed refreshments. There are wires on an '83 at the local junkyard but they look really old so I doubt they are worthwhile. I have the FPR off that car so I do have one to try swapping if the new FPD doesn't do the trick. I might have time to do the FPD tonight, and I can also put in the new plugs I have. Then I can try driving it to work in the morning. Have I mentioned I have a bike permanently residing in the back of the car these days so I can actually get places?

konakat

Couldn't get the damn fuel line off the bottom of the damper last night. It's soaking in PB Blaster now and I'll give it another go tonight. Any tips on getting it unstuck without tearing the whole damper off the fuel rail?

Lecrok

If you can remove the FPR and since you have one, try that first. That was the issue I had on my '87 924S. The car would shut off after running a few seconds because the fuel pressure was too high. If I pulled one of the fuel injector cables off and ran with three injectors it would keep running, ergo FPR fail.

konakat

Still can't get the damper off the rail. I got the lock nut loose but I realized there is just a cap on the bottom, not an actually fuel line. That cap just won't budge and it has to move in order to get the lock nut off. I gave the FPR a shot and there wasn't enough room to fit a 22mm wrench, so I decided to pull the whole fuel rail and work off the car. One of the injectors decided to detach from the fuel rail instead of pull out of the head, so now the engine is covered in fuel. Still haven't been able to get the FPR or damper to budge, this is turning into a hellish job. Probably won't have much time to work on it in the coming weeks either. Ugh.

F18Rep

Sorry for the interuption... We sent out a batch of these with the wrong gauge. I was in the hospital at the time and family was helping. If anyone has one of our fuel pressure gauges, it should have a 7 bar (100psi) gauge - we will ship you a correct gauge, just email me...BruceArnn@arnnworx.com ...Bruce