First - I have had this car for about 4 years and I have tried to figure out what is causing it. It has done it ever since I bought. It is a 305 TBI auto w/OD. When idling in drive or even goosing the gas in park it will die. It also may die if I am in reverse and switch to drive while turning the steering wheel. It doesn't do it all the time. Maybe once a month or maybe 5 times a week but never is consistant. It does seem to do it more when it is hot and humid, but it has done it in dead winter also. Any other time it runs perfect. Example, I could be sitting at a stop light waiting for the light to change and all of a sudden the car just dies, it will restart with no problems and may not do it again for a month or may be a couple of hours. That's what puzzles me. This a list of things I have done to try and correct this with no luck.

1. replace fuel pump and filter, fuel line
2. replace both injectors and checked fuses
3. Cleaned carb.
4. Timing
5. Premium Gas 91 oct.
6. Replace Gas Cap


2nd - I have noticed here just recently after having the valve seals replaced that my oil presure guage is acting funny. When engine is cold the needle pegs out and stays thay until it warms up. During warming up the needle bounces alittle until it sets still at normal pressure at idling. Now when I give it gas the needle again pegs out and jumps around. The car runs as it did before the seals were done except it doesn't smoke any more. It acts as if there is a voltage problem. Things I have done to fix this problem but have not worked.

1. changed Oil and filter
2. had oil pump checked

Sorry for the long read but I tried to cover all areas of concern.

Any help would be greatly appreciated.

Carl

 

As for your stalling.. I have the exact same problem.. it stalled at the red light today too. some times mine will not restart .. unless I opened the throttle a bit when it tried to fire. But it has not done that in quite some time.. What I tinkered with last, which seem to stop the problem from happening for many months was clean and reset the IAC (Idle air control). I even tinkered with the EGR. I sure wish I could scrap the EGR all together. I have a feeling though the EGR is more of the problem than the IAC. I know this stalling thing really sucks.. But it's kinda nice to see I'm not the only one.. Perhaps if there is enough of use, we can share our experiences, and completely solve this problem.

Oh, what I really hate about this dumb problem, is the ECM never gives any kind of code. You'd think something would trigger a code when it just up and shuts off.

 

Well with the oil pressure problem I would replace the sender it sounds bad.........here is the kicker if it senses the oil pressure is 0 the sender will cut your FUEL OFF. This is done for to be safe so the fuel pump will shut off if the engine dies.........So yeah that could be both problems in one.



Brian Felts

 

I will check out the sending unit. I was thinking about that too but never thought it was connected to fuel pump. It does make sense for that to do that. But the ECM does not give off any codes, which I figured it would.

Thanks for the help, I will let you know if that works.

Carl

 

The strange thing with mine is my oil pressure has never shown any problems.

 

This is how I found out....... I was getting ready to prime the oil system in my new motor and as soon as the oil pressure came up (with the key off) fuel started shooting out the fuel lines.

FastElectrics: as far as your problem I would think its a TPS or IAT. Could check your fuel pressure but I would think the computer is getting a bad reading.


Brian

 

The fuel WILL NOT be cut off when the oil pressure goes to zero. The oil pressure switch is a back up power supply to the fuel pump when the ECM fails. That is why your fuel started to flow when the oil pressure went up. An alternative supply was achieved. It does not work the other way round. It cannot shut the fuel supply off.

When the ECM senses ignition pulses it will fire up the fuel pump (except for the initial 2 seconds or so). If not, normal oil pressure will supply power to the pump.

Andy.

 

In a perfect world you are right but when you get a sensor failing then it could very well happen.........now that you have sent your opinion what do you think is wrong with his oil pressure and the car stalling?????????



Brian

 

Andy,
now you've p!ssed Brian off, can I have an answer, 'cuz mine does that about once a month with no codes!

Paul

 

No not pissed but we need to give our brother some ideas to get his ride right..........any ideas with some knowledge behind them could be the right one.



Brian

 

Hi All.
Sorry to **** you off! Not intended at all! Honest! That statement was a very common misconception. And I don't want anybody changing something that is unecessary! I've been down that road before!

We need to check that the oil pressure isn't doing what the gage says it is! I would substitute a mechanical gage and sensor in temporarily to check. Obviously if it is all okay then that dreaded sensor is faulty! (So it may have to be changed after all!!) If that isn't the problem we need to check further. I would be very keen to know if the oil pressure was okay or not!!

Alternatively, lets do a simple oil pressure gage check.
1) Disconnect the oil pressure sender. Place ignition switch to RUN. If the oil pressure gage reads high, go to 2 below. If it does not read high, check the TAN wire for a short to ground, the instrument cluster printed circuit for cracks or flaws and gage connections at back of cluster. Repair or replace the oil pressure gage if all check out.

2) Connect the TAN wire at the sender to ground with a jumper wire. If the gage reads low, repair/replace the sender. If it does not read low, check the TAN wire for an open circuit, the instrument panel for breaks or flaws and gage connections. Again, if all check out, replace oil pressure gage.

My bet here is that a wire has been disturbed since the heads have been removed. Why not do the waggle test (waggle every wire in the vicinity of the sender while someone watches the gage-engine running).

Right then. The stalling. My opinion? I would check for any vacuum leaks first. If in doubt, replace the pipe(s). Don't forget the breather pipes. Then check the purge valve at the carbon canister is not sticking. If it does stick, it will let fuel vapour in under idle conditions and so it won't idle! If you see what I mean! I would disconnect the wires to the canister to see if it happens again.

Also, I would check the TPS is giving a correct signal. Check it's output with a voltmeter or oscilloscope. The voltage should go up smoothly as the throttle is opened. If in doubt (and the car has a high mileage on it), change it. They can't last forever since part of it is mechanical. I would be very interested in the idle voltage being consistent every time the throttle shuts. Remember, the ECM will not register any fault codes if the TPS gives odd readings, but within tolerances. If it gives a reading that is "implausible", it will then register a fault code.

Hope this helps a bit!
Let me know if you want any wiring diagrams or specs.

Andy.

PS My apologies again Brian!

The EGR above is good advice. Make sure it isn't sticking.

 

Just thought I'd post my car stalled again today.. sitting there at the red light, in nutral, oil pressure ok, temp ok.. just shut off as if I turn the key.. rather anoying.. But thanks for the tips in the previous post.

 

I was going to work on my car today and it has rained off and on all day. It hasn't rained here in 2 months. It never fails. Does it seem to stall more if there are good looking chicks next to you at the red light looking over at you and gazing at your car and then KUPLUNK! she dies, how embarasing. Speaking from experience.

I think I am going to start at the oil pressure switch and work from there. when the sun shines agaqin.

Carl

 

FastElectrics.........are the computers throwing any CODES? this is really getting me down. I just can't imagine could be the fuel pump but usually it dies and then will not start again.



Let us know
Brian

 

My car was doing this when I had the 2.8 in it, it was really wierd, the funny thing was it seemed to stall at the same spots around town...just a fluke I'm sure. Ended up being the ignition module. Changed that and the pickup coil and the problem went away. Just my experience with stalling.

 

Brian Felts : that is the thing that sucks.. the ECM has never given me a code for anything... yet it says it's working fine. and most of the time it does.. I had the same problem before I replaced the fuel pump also. so I know it's not that.. Fuel filter has been replaced. ect . There are a few things I'll check this weekend .. I was hoping though that the Air/Fuel ratio guage would show something .. but it acts normally, doesn't stay to one side or another.. so I don't know if it's a lean stall, or a rich stall.
The injectors don't leak, and spray properly also. If it wasn't for the good gas mileage I get, I'd gladly ditch this stuff and go carb.