98 regal gs won't start when cold

[rzb88]

Hi,
I bought a 98 regal gs, a week ago, 128k miles, seems to run fine.
Last few days it will not start when cold. Turns over, but does not start, then finally it will after about 1-2minutes. Seems to run great, no other problems with the engine. Today, it stopped when I got to a traffic light 1 mile down the road. I restarted, and drove 40 miles to work, and it was fine since. It is setting a 'service vehicle soon, anti-lock' but I can't believe that is related. (that is next on the list to fix).

Any ideas? I have checked the plugs, they appear fine, in gap, and like they have been changed not long ago. New air filter, injector cleaner.

Is there some type of module that makes it run richer when cold, to ease in starting?


Thank you,
Ron

[BNaylor]

If you are getting a SES light best thing to do is get it scanned for odb-ii codes.

Also check fuel pressure at the fuel pressure regulator (FPR) and make sure it's in specs. It should be checked with vaccum on and off at the FPR. Your GS has a two speed fuel pump and a fuel pump resistor that can go bad giving similar symptoms.

Finally, it may help to clean the throttle body with carb cleaner, especially the idle air control valve (IAC) seat. Plus the MAF sensor should be cleaned with electrical contact cleaner.

[rzb88]

Originally Posted by bnaylor3400

If you are getting a SES light best thing to do is get it scanned for odb-ii codes.

Also check fuel pressure at the fuel pressure regulator (FPR) and make sure it's in specs. It should be checked with vaccum on and off at the FPR. Your GS has a two speed fuel pump and a fuel pump resistor that can go bad giving similar symptoms.

Finally, it may help to clean the throttle body with carb cleaner, especially the idle air control valve (IAC) seat. Plus the MAF sensor should be cleaned with electrical contact cleaner.

Thank you for the reply.
I have a bit more info:
A friend has an 'autotap' and we hooked it up tonight.
Gets a : P0336 CKP sensor in the DTC I think it was.... got this 18 times.
He (knowing more about cars than I) thought this would not lead to hard starting but more a car that wouldn't run at all. Also tested the fuel pressure and it as 42psi. (is that low?)
Monitored a zillion other things and he said he didn't see anything out of normal. We did NOT however test anything cold, as I drove the car to his place. I guess the next test could be leave the car overnight and see what codes it gets in the morning.
Any other suggestions you have would be great.
Ron

[BNaylor]

The fuel pressure reading is on the low side but not totally bad. The specs for your fuel pressure with vaccum disconnected at the FPR in the ignition on position not engine running is 48 - 55 psi. With vaccum connected and engine running it should read in a range of 45 - 55 psi. You might consider re-test under these parameters.

The symptoms on a crank position sensor vary. Hard starting, no starting, engine dying after a certain period of time. But if the PCM is giving a CKPS DTC error code it is probably valid. A lot of times no error codes will show with a bad CKPS. Sometimes a TRAC OFF light or ABS light will come on when the engine dies while car is in motion.

[shaws5]

change the crankshaft position sensor they can do crazy things

[HotZ28]

"Is there some type of module that makes it run richer when cold, to ease in starting"?
The CTS sensor tells the computer what the operating temperature of the engine is. When the engine is cold, it needs more fuel to operate correctly, and if it is cold enough, it will inject a large quantity of fuel to start the car. This is called Cold Start Enrichment and replaces the function of a choke.

The computer sends a 5-volt reference signal to the CTS sensor. As temperature changes in the coolant, the electrical resistance of the CTS sensor also changes. Start the engine, and check voltage with the wiring connector hooked up. Record the voltage changes as the engine warms up to operating temp. i.e. 120, 140, 160 & 180. You should see close to the full range of voltage (0-5.0V) during this test. If it does not change, or it hangs around mid range (2.5 V), replace the sensor!

[rzb88]

Hey guys,
Still trying to solve this issue, so took it in to the local shop.
They said, not sure but think it is the fuel pump.
Said it is slightly low on pressure 40psi, but is drawing too many amps or too few I forget what he said.
Said this could cause the engine to not get enough fuel when engine is cold.
$600 bucks to replace.........
This sound true or bs?
Ron

[BNaylor]

Originally Posted by rzb88

Hey guys,
Still trying to solve this issue, so took it in to the local shop.
They said, not sure but think it is the fuel pump.
Said it is slightly low on pressure 40psi, but is drawing too many amps or too few I forget what he said.
Said this could cause the engine to not get enough fuel when engine is cold.
$600 bucks to replace.........
This sound true or bs?
Ron

40 psi is too low for a L67. But it depends on how it was tested. With ignition on, not start (fuel pump prime), the fuel pressure should read 48 - 55 psi. If you don't get these readings at this step, it indicates the fuel pump has gone South or fuel filter is clogged. Typically, a Regal GS should read around 52 psi or higher. Now if the engine was running and vaccum to the fuel pressure regulator is connected it should read in a range of 45 - 55 psi. The difference with vacuum on or off at the FPR should only deviate 4 to 7 psi. Excessive difference indicates a bad fuel pressure regulator. It's located on the passenger side of the engine, odd bank cylinder fuel injector rail by the supercharger snout.

BTW - A defective FPR can give similar symptoms- hard starting too. Remove the vacuum line and see if you see fuel contamination. If so the diaphragm is ruptured. It's a lot cheaper to replace than the fuel pump and easier.

[BNaylor]

I forgot to mention that you have a two speed fuel pump. In a L67 GS there is an extra relay in the engine compartment fuse box. It's the fuel pump high speed control relay (#18). It may not be energizing due to a defective fuel pump resistor. Symptoms are hard starting and engine cutting off from a few seconds run time to a few minutes. It's located behind the passenger side headlight, inner fender, by the windshield washer reservoir.

There is a troubleshooting and bypass procedure to determine if it's the resistor available at GlubGP.

[rzb88]

Thank you.

I talked the the repair guy again, and agreed to have the pump replaced.
He said it is only drawing 6amps, and should be at 10 amps.
He is confident that is the problem, yet, said it not, the pump was on it's last legs anyway.
That amp reading ring any bells?
Ron

[BNaylor]

Originally Posted by rzb88

Thank you.

I talked the the repair guy again, and agreed to have the pump replaced.
He said it is only drawing 6amps, and should be at 10 amps.
He is confident that is the problem, yet, said it not, the pump was on it's last legs anyway.
That amp reading ring any bells?
Ron

Chances are the fuel pump is the cause but you never know. I'm from the old school where I look at other known possibilities and properly troubleshoot before shelling out $600 that may or may not fix the problem. I don't agree with the mechanic that the fuel pump should draw 10 amps. It's fused with 15 amps. Part of the GM service process on the fuel pump is hooking up a fused 10 amp jumper wire direct to the fuel pump. Of course using a Tech II machine for this type of trouble is better than guessing. But the fuel pump could draw up to a possible 10 amps.

Sometimes instead of looking at current draw maybe voltage should be checked. With the speed control relay energized the fuel pump will have 12v at the input. When not energized around 7 volts. If a constant 7 volts is present at the fuel pump even with the speed control relay appearing to be energized then that may explain the lower current draw.

BTW - The mechanic's profit on replacing a fuel pump versus other causes is pretty good. In my case I'd DIY the fuel pump replacement and save at least $300 in the process. Good luck and hope you get it fixed.

[rzb88]

Ok guys,
650 bucks later, I have a new fuel pump. Garage, said, no problem, car starts fine. They left it outside 19degrees here lately, and it always starts. I got it back. Drove to work the next day about 40 miles. After sitting in the parking lot for about 3 hours, when I went to go to lunch it still was doing the same crap. Hard start, crank crank and finally after about 1 min will start.
It was a cold dry day out. Other issue garage said, was plug wires were rusted on two cylinders and should be replaced. I can do that. But plug wires don't seem to be the issue here. I could see if it was when wet out. Yesterday was dry. Cold yes. But dry.
It actually seems if the car has been sitting a short time it is harder to start, yet it starts fine if it is warm. It is like that 3 hour setting. If it has been sitting all night it starts fine. This was the case when it was sitting for 2 days outside, when I picked up from the repair place, or it it sits all night in my garage. I guess I could leave it outside in my driveway over night and see if it starts then.

So..........maybe that fuel pressure regulator?
What is the next logical choice?
Thank you....
Ron

[BNaylor]

Originally Posted by rzb88

Ok guys,
650 bucks later, I have a new fuel pump. Garage, said, no problem, car starts fine. They left it outside 19degrees here lately, and it always starts. I got it back. Drove to work the next day about 40 miles. After sitting in the parking lot for about 3 hours, when I went to go to lunch it still was doing the same crap. Hard start, crank crank and finally after about 1 min will start.
It was a cold dry day out. Other issue garage said, was plug wires were rusted on two cylinders and should be replaced. I can do that. But plug wires don't seem to be the issue here. I could see if it was when wet out. Yesterday was dry. Cold yes. But dry.
It actually seems if the car has been sitting a short time it is harder to start, yet it starts fine if it is warm. It is like that 3 hour setting. If it has been sitting all night it starts fine. This was the case when it was sitting for 2 days outside, when I picked up from the repair place, or it it sits all night in my garage. I guess I could leave it outside in my driveway over night and see if it starts then.

So..........maybe that fuel pressure regulator?
What is the next logical choice?
Thank you....
Ron

Sounds like the next logical choice. It's not that expensive compared to a fuel pump and easy to change out. Do you have any updated fuel pressure readings since the fuel pump was replaced?

Also, in a worse case situation and fuel doesn't resolve it you could have an ignition problem. The crankshaft position sensor can give a similar symptom.

[rzb88]

Ok thank you.
I am pretty handy at car work, yet by no means an expert. How do I replace that fuel regulator?
Thanks,
Ron

[BNaylor]

Originally Posted by rzb88

Ok thank you.
I am pretty handy at car work, yet by no means an expert. How do I replace that fuel regulator?
Thanks,
Ron

Its an easy DIY job. See link below. It is for a Capser HP fuel pressure regulator but the same process for any L67 equipped "W" body. Just disregard the adjustment part because a OEM or replacement FPR is not adjustable. Good luck!

http://www.grandprix.net/upgrades/fpr.html