Strange Problem

[Newbie Mechanic]

I own a 1988 Bonneville. It runs like a champ and I have never had problems with it. I drove it to the college I attend and didn't hear anything strange. After I left the college I drove to a grocery store. I tried to start it up after I was done, and it would not start. I thought it was due to the cold so I put a bottle of HEET into the tank. I let it sit overnight and the next day she fired right up. I thought that would be it. Until it did it again a few weeks later.

It has spark on at least one spark plug.
It has a brand new battery.
It cranks just fine, no grinding in the starter.
If I leave it alone for a few days it fires just fine.
I have just replaced the fuel filter.

I cannot for the life of me figure out what is wrong. I have heard it could be one of three things, or all three. Either a bad crankshaft sensor (I bought a new one already), bad ignition coils, or a failing ICM. If anyone has any ideas, I would greatly appreciate it. I work at a Sears Auto center so I know a little bit about cars and I have access to tools. Has anyone had this happen before?

[myfirstbonnie]

I had the same thing and it was my fuel pump. They get warm and stop running. Check the fuel pressure on the rail with a gauge.

[Newbie Mechanic]

Using just a regular tire gauge? Also, I should just set it to on without trying to start it, correct? What are the specs for a good fuel pump? Sorry for all the questions. I love this car and am willing to spend my whole paycheck to get her going again.

[myfirstbonnie]

No. some places will rent or loan a fuel pressure gauge set.

It will plug into the rail, turn the key on and see what pressure is built.

Then turn the key off and let it set and see how fast it bleeds down.

Then start the car and see what the pressure is with the engine running.

[Newbie Mechanic]

The car won't start at this time. It is steadily getting worse with how long it stays out of commission. It has roughly 188,000 miles on it but as always run strong since I got it. It is just spinning like it wants to fire but it isn't.

My next test is to try to start it, then see if my plugs are wet. If they aren't, I can narrow that down to my fuel system. Another person I work with has said that it could be the fuel injector (either not getting electricity or a blockage). Thank you for the fuel pump idea though, should give me a better idea of what I'm working with.

[J Wikoff]

You can put a 194 bulb in an injector's wiring connector and try to start the car. If the light flashes, you've got power to the injectors.

[Newbie Mechanic]

That will help narrow down my electrical problem. Is there any way to see if maybe my injectors are plugged? I really noticed it after I let the tank drain down quite a bit. I filled up completely, then drove it for a few hours the next morning. When I tried to start it, it sounded like there was no gas coming in (cranks but no fire). I replaced the fuel filter and blew into the end to see rust and black junk fall out. I'm also assuming it was a factory original (well, it was an ACDelco) plus it was fairly rusted.

[J Wikoff]

You could remove the fuel rail with everything still attached, put a cup under each injector, and watch the spray patterns while someone cranks the engine. Also, if you crank it for several seconds, enough to get a measureable amount of fuel, you could look for different amounts of fuel from one injector to another.

If you do need cleaned injectors, we've got a good vendor here in the links page, that can get you a really good matched set of rebuilt injectors for a good price.

[Newbie Mechanic]

That sounds like a good plan. All the mechanics I've spoken to are stumped as to why it won't start sometimes. This might be turning into a good summer project, seeing as it's STILL snowing here in Great Falls. Thank you guys for all your help. After I try the crankshaft sensor (couldn't hurt seeing as it's already paid for) I'll update it's status. I'll also post any other things I have noticed. Another thing that just came to me, once it wouldnt start while I was at work. It was really dark when I was leaving but I did notice alot of fluid just between the LF tire and the driver seat. It smelled like fuel but without a really strong odor. We pushed it into the shop the next day, I couldnt find a leak, added about two gallons of fuel, it fired right up, ran for 20 minutes, then I drove it home the next day. I put it on our lift while running to see if anything would drip. Not a thing.

[J Wikoff]

Have you tried pulling codes?

http://www.pontiacbonnevilleclub.com/fo ... =51&t=8689

[gmman]

i own a 1988 bonn le. fuel pump expired at 192000. sympton, wouldn't start. towed to Pontiac dealer.diagnosed as bad fuel pump. about $400 to replace parts and labor. that was years ago however. fuel gage was never as accurate afterwards mostly at the low fuel point (less than 1/4). on the bright side, car now has over 325000 orig engine and transmission. only other thing replaced other than usual stuff, timing chain. OH! sympton, wouldn't start then either. jumped timing. $750 at dealer. years ago.

[Newbie Mechanic]

I just pulled the codes:

13 - oxygen sensor (open circuit)
41 - cam sensor circuit
48 - misfire diagnosis
63 - exhaust gas recirculation check

Could it be my cam sensor?

[turkeykiller]

on a day that the car is not starting just turn the key and listen to see if you can hear Fuel Pump.
on a day that the car starts turn it off and put the on and listen to see if it has the samesound

[J Wikoff]

I don't think the cam sensor can make the car not start. It would just cause sluggishness. The PCM uses it for exact injector timing, but does not shut off the injectors if there's no signal. Instead, it just defaults to some "retarded" timing. The cam and crank sensors share some wiring, though, and a bad crank sensor will prevent the engine from starting.

BTW, it might be time to get a new O2 sensor. If that code is constant, it's killing your fuel mileage.

Disconnect the battery for a little bit, and see what codes come back after you get it started again.

[nunesjeff]

I'm all about the fuel pump & The list of codes... Mine had the 41 and a 13 and it ran so crappy.... My Bravada just did the same crap! Except..... The strainer was failing and plugged up the inlet of the pump...