This is not your average no start thread. I have read all of those, so cast your pre-judgements aside!

Sat afternoon, about 80 deg outside, driving normaly, just coming off a moderate acceleration, it felt a little odd/jerky. So I decided to just drive it normal. No issues, until the next time (same drive) I decided to go past 1/2 throttle. This time bucks and stumbles more/worse. No noises while coasting, only when stepping on throttle did it stumble.

So I downshift to 2nd to turn into my neighborhood, slightly uphill, and it has no acceleration at all, and there it stalls. 4 houses away from my driveway. After a tough push uphill, I start doing the usual checks. Cranks only, no fire-up.

Fuel at the rail, PSI unknown at this time (let my FPG at work), spark at the coil, spark at the wire, spark at the plug. So spark is good. I smell fuel from the tailpipe, and I have injector pulse (noid light). It did seem a little weak, but it was there. Couldn't check Voltage because I was by myself and had no one to hold my meter leads.

Here's what I have done/checked. Vacuum lines are intact/new. 1/2 tank fuel added the day or two before this happened. Checked ref. sensor resistances = good. The tach DOES bounce while cranking. Had previously re-set my TPS a few days earlier but it showed no issues after resetting it, and I don't think it would just act up 2 days later (yes screws are still tight). DME relay has been replaced with new-in-box part. Timing belt tensions are still good. Unplugging Air flow meter has no effect. Unplugging a fuel injector has no effect.

So now my questions. The car sat undercover for aprox 2 years by the PO with less than 1/2 tank fuel. I used some of it getting it running again and during test drives etc. Could I have stirred up a bunch of crap after fueling that finaly made it's way to the filter? Could the air flow meter have crapped out?

I think I have all my bases covered on my tests with the exception of Injector voltages, and actual fuel pressure during KOEO or during cranking. Please enlighten me on what I may be missing. THANKS!

 

I had simmilar symptoms when the refrence sensor connection crapped out on my early car. Without the refrence sensor signal, you will get a spark and the tach will bounce, it's just that the spark timing is off.
If I held the throttle wide open and cranked for like 20-30 seconds, the car would slowly stumble to life, and run really crappy (really rich), and only while the throttle was wide open. Slowly as it gathered speed, it would start to smooth out; at around 4000 rpm, it ran almost normally.
In my case, it was the sensor side of the connection that was bad, so it was an easy fix - just swap in a new sensor.

 

Sounds like it could be a fuel filter.

Couldn't hurt to give the crank sensor wires a good wiggle to cure what JPK mentioned.

I like to disconnect the TPS and AFM individually as the car will start and idle with both sensors disconnected. It gives you a bit of easy diagnostic info on 2 parts that are relatively common failure items.

 

I have a reference sensor that will be here today, ant other ideas?

 

OK, I got the new sensor, and b4 I dug into replacing it, I started looking at the harness side of the connector for the ref. sensor. It was cracked and I could see exposed wiring inside the crack. I have a donor harness, and proceeded to replace the connector. Little did I know that the wiring has a spiral wrapped 3rd wire that goes around the other 2 cased wires. Any repair done on this is going to look like absolute crap!!

Has anyone done this repair b4? Any tips?

Also, the ref. sensor appears to be corroded into it's hole. By "walking" it back and forth it should eventualy free up right?

 

The spiral wrapped 3rd wire is likely a shielding wire. A little heat shrink tubing should make the repair look decent. I wouldn't worry about wrapping the 3rd wire over the repaired joint...a half inch of unshielded wire in that area is nothing to worry about IMO.

I have replaced the wiring to the crank sensors, however I replaced it all the way back to the DME since it seemed my issue was somewhere mid-stream in the main harness.


You should be able to wiggle the sensor out of its hole, but you may want to see if the car fires up after fixing the wiring issue on the harness side just so you know if that was really a problem or not.

 

someone might frown on me for this "ductape" fix, but you might try wrapping that section in tin foil to act as shielding, then wrap all of that up in electrical tape.

 

My only concern it, that the ref sensor connector is a three prong. Only two of these wires are cased, the other terminal is this shielded/spiral stuff.... I have a brown wire, a white wire, and the shielded stuff. I would assume that the shielded stuff is part of the signal/ground for the sensor. I will look at the wiring diagram when i get to work this morning.

 

How much of the 2 year old gasoline is left in the system? Perhaps you need to run a couple of tanks through it to clean it all out. Maybe some Techron would help.

 

very little, ran it into reserve b4 fueling.

 

OK, got the car to the shop yesterday where most of my tools are, and started digging deeper today on it.

Checked compression, even across the board. Replaced the ref sensor and repaired the wiring as described above. Pulled spark plugs, looked sooted up from trying to start, but not wet with fuel like I would expect from trying to start so many times. Double checked my timing marks, and they are dead on. Fuel pressure is 39 psi before the regulator, and flow seems good by holding a bottle under the line with it off and cranking over.

I have a fuel filter that will be at the shop at 8 AM that I am going to try, and am going to add some more fresh fuel. What are the odds that something got through the filter, past the regulator, and clogged the recently cleaned injectors? I have never seen this happen in my 12 years of wrenching, but when it comes to my Pcar, I've learned that anything is poss. Is there a higher possiblility that my FPR is bad? I've tried unplugging an injector and it made no diff, and the car just cranks and cranks and cranks. What am I missing!!!!

 

bumpage

 

OK, finaly got this one fixed. And it's my own damned fault for jumping the gun. I removed the dist cap to make sure the keeper was still there for the rotor. I did not look for the OTHER bolt that holds the damn shaft in place. STUPID STUPID STUPID!

After a new FPR, FFilter, checking timing AGAIN, fuel pressure, spark, changing Ref sensor, and a whole bunch of other stuff, it ends up being something as stupid as a bolt! At least I now know that EVERYTHING on my car should be OK for at least a week....

Thanks for all the ASSistance. Sorry for overlooking the obvious. Time for a beer...