3800 cold start problem

Hello,

I have a 90 oldmobile eighty eight. The car starts right up and runs great when the weather is warm. Now that winter is here it take forever to start when it cold outside. Sometimes i have to crank it so long i have to throw a battery charger on it. It will crank and crank, and fire every once in a while. The long i crank it the closer together it will fire and eventually start. I can smell a slight hint of gas when doing this. I almost sure it the coolant temp sensor. I know that if it is bad, it will add a ton of fuel because it thinks it colder out than what it really is.

Are there more than one coolant temp sensors on this car, if so which do i replace? I think its the one underneather the throttle body. Just wanted some insight.

Also when it does start it runs rought for less than 5 seconds then its fine. Thanks


Register now (free) or login to remove ads

Until you get the sensor figured out, hold the pedal to the floor when you go to start it, usually if it fires up when you do this you know it`s getting too much fuel, the wide open throttle position gives it enough air for it to fire the excessive fuel in most cases.

I have tried this. It pops a bit and will fire, but it doesnt really seem to help.

I just found an ohm range for the sensor i will check it tonight.

The temp sensor for the puter will generally be a two wire, black and yellow.

WOT on most vehicles will shut the fuel off if below a certain rpm. This is handy for starting a flooded fuel injected engine

__________________
Artificial Intelligence is no match for Natural Stupidity



Chet

Check the fuel pressure. Bad numbers can cause some unusual problems. Also some of the Gm fuel injected cars had a cold start injector just for cold starting. My 86 Celebrity had one don't know if yours does. On my car it was a 7th injector mounted in the end of the intake.

I agree, check fuel pressure first. Check the coolant temp sensor second. Depending on how it fails, the sensor can either cause too much or too little fuel to be sent to the engine. For example, if the sensor thinks the engine is already warm, it will not send enough fuel for a cold engine to start. My money is on this failure.

There may be an air temp sensor as well - check that. Note that the SFI 3800 motors do not use a cold start injector.

I have exactly the same problem and I can assure everyone that it is NOT fuel related. The following is what I am experiencing. Any help is appreciated.

Vehicle: 1994 LeSabre with 125K. Owned since new.

Location: Chicago

Check Engine Light Codes: NONE

Problem: My car has started to exhibit a "hard to start condition when cold." When the Ambent temp. is ~40 degrees or < the car becomes increasingly difficult to start. The colder it gets, the harder it is to start. However, if it warms up to ~40 or higher, it starts fine.

Parts Replaced: Coolant Temperature Sensor, IAC, MAF, EGR, ICM, fuel pump, fuel filter, sending unit, gas tank, starter & battery. I also tested the coil pack; however, the primary and secondary resistance on all three coils is within spec. Furthermore, I dug into the engine replacing the Plenum (and it's gasket), cleaned the throttle body, the lower intake manifold & replaced the LIM gaskets. Also checked the fuel pressure regulator and it is NOT faulty. All of this work was done during December.

Since January, I have replaced my ignition wires with a set of brand new BOSCH premium ingition wires. Before buying these wires, I brought my trusty multi-tester with me into AutoZone and actually checked the resistance of each wire and found that each wire had very low resistance (this compared to my original wires), so, I was optimistic, but after installing these new wires they did nothing to correct my problem. I then replaced my three coils and here too I checked the resistance of these new coils before buying them. The Primary Reisitance of each new coil was approximately 0.9 ohms for all three coils which is within mfg. specs. (0.5 to 1.0 ohms) and the Secondary Resistance for each new coil was approximately 7.5 to 8.2 ohms (which was also well within the 5.0 to 10.0 ohms mfg. specs). Finally, I replaced the Idle Air Control vaule/motor (again), to positively rule this out and I checked all of my vacuum lines (they are in great shape); however, this gremlin in my engine lives on.

Someone told me about carbon build-up in my intake ports; however, I cleaned these ports real good when I had the upper Plentum and lower intake manifold out of the car a few weeks ago. The LIM gaskets were both shot so, at least my time and money was worth it here.

I am just about out of parts to check or replace to fix this cold start problem. Does anyone have any other suggestions?

Any help is appreciated.

This thread is two years old. Copy your question and start a new thread on it.