Hello all. Shade tree mechanic,farmer, help seeker. I have a 1993 b2600i 4x4 manual transmission. I love and hate this truck. I bought it many moons ago, had ecm rebuilt. have rebuilt the engine. put several heads on. Ok on to the current problem. Truck decided to take forever to start. You crank and crank. stop and crank some more, it eventually catches a couple times and then once it starts, its great for the rest of the day. Will start easily from then on. Finally had time to do some checking, Checked fuel pressure, when cranking is aroud 40 psi. Stays above 10psi overnight. Checked spark, its there lol. Might be a little weak possiably but its there. Checked compression, numnber one was low at 125, the rest were 150. Should run ok correct? (not my every day vehicle) Pulled plugs out, they are black. Cleaned but didn't make a difference. Truck now won't start at all. Just cranks. So I have fuel(possiably too much?) I have compression, I have spark(possiably weak)....I also am bypassing the starter switch in the cab and running a switched wire to battery for remote start.
Temp sensors?
Fuel injectors?
Fuel pressure regulator? (has vaccum to it)
Coil?
ECM?
New Truck?
TNT?
Any help and or input would be greatly appreciated. And yes I have gone throught the fourms, and will continue to go through them. Thanks again for any help.
Signed cold in Nebraska.

 

Nebraska? Spent a lot of time in Lincoln...
I suspect that you have a bad cold temp sensor. I don't know where it is located on your engine, but it is usually a weather pac connector. If the ECM is not receiving a signal from it, it will not add fuel on cold start.
I am pretty sure that there is an intake air temp sensor which may also be a problem.
I may be wrong, but I have found that is the usual problem.
Just to confirm, try giving the intake a shot of ether. If it starts, I would guess that is your problem.
Oh, and change your fuel filter if you haven't yet.

Hope this helps

 

Ya I'm about 30 miles west of Lincoln. I have tried ether. Doesn't want to fire on that. So I'm guessing week spark or too much fuel. Maybe. Thank you, I was thinking air intake temp sensor may be part of the problem.

 

Try this to determine if it is a fuel delivery issue.......

Remove the rubber air delivery tube from the aluminum air intake casting that is bolted to the valve cover (on top of engine)......

Squirt a stream of gas into the opened end of the aluminum air intake casting......re-install rubber air intake tube.......

Crank the engine over......with the key......if your engine starts, then dies (fuel squirt is depleted) then you have a fuel delivery issue.

If your engine does not start, I would rig a wire from the battery (+) terminal to the (+) side of the coil so you'll know the coil has power.......then try to start the engine again (without adding fuel this time).

These ignition switches are known to wear out and one symptom is for the bad ign. switch to not provide power to the coil while you hold the switch in the start position! Give it a shot and let us know what you find out.

One of my B2600i trucks.....

 

BTW.....if your rubber air intake tube is not completely sealed/closed, then you may not be able to start the engine also........although, without the air intake tube in place, if everything else is working fine with the engine, the engine will start, but then die right away........that tube MUST pull intake air across the MAF sensor that is located at the entry end of the rubber hose......otherwise the ECM cannot determine if the engine is receiving an air intake or not.

Another issue could be with the MAF electrical harness connection.......the rubber seal where the wiring harness connects to the MAF will become brittle and crack and then sometimes the terminals will corrode.......but this does not happen too often.

 

have a 1991 b 2600 4x4 and had the same problem. started fine in warm weather but wouldnt start when cold outside. had to pull air inlet hose off and spray carb cleaner in it to start it if I didn't want to run battery down. started fine rest of the day if didn't sit too long. found the connector at the distributor was literally falling apart. found a replacement connector on ebay and replaced it. Problem solved.