Another hard starting when cold

[big66440]

I have an 89 renix 4.0/AW4 D35,It's a PITA to get it to start when cold (engine temp) I know renix engines crank for a bit before they start but I have to sit there and crank it for a good minute before it even starts sputtering. I recently replaced the fuel pump (good pressure),fuel filter,cps, plug wires, o2 sensor,cleaned the IAT and throttle body thoroughly,I've checked resistance values on coolant temp sensor it seems fine, checked fuel pressure regulator it's also ok,it's pretty much the last thing i need to figure out to make my truck run perfect but I'm all out of ideas,please help.

[big66440]

nobody? i have access to a snap on mt2500 scanner if that helps?

[carnuck]

Try swapping the fuel pump relay for one next to it. I had the same problem and that was the cure. (even made me late for work!)

[big66440]

I've already tried it,and it did nothing it's pretty damn embarrassing getting into my truck with my mechanics uniform in the morning and having that happen :oops: lol

[mythreesons]

I have an 89 renix 4.0/AW4 D35,It's a PITA to get it to start when cold (engine temp) I know renix engines crank for a bit before they start but I have to sit there and crank it for a good minute before it even starts sputtering. I recently replaced the fuel pump (good pressure),fuel filter,cps, plug wires, o2 sensor,cleaned the IAT and throttle body thoroughly,I've checked resistance values on coolant temp sensor it seems fine, checked fuel pressure regulator it's also ok,it's pretty much the last thing i need to figure out to make my truck run perfect but I'm all out of ideas,please help.

 

 

I see that you say that all those parts have been replaced, however does all that stuff work properly? Does it act the same way if the engine is warm? Might be a clue there.

 

Cold engine needs good fuel delivery, air and good spark. Check those three under cold conditions and see what you find. Don't bother with the scanner it will tell you less than what you'll get from a clear thought process and a digital multi-meter. Personally, I would start with grounds and check the spark. If your spark is suspect, check the CPS (If you have good spark, the CPS is working). See Cruiser54's recent posts on CPS testing.

[phenryiv1]

I have found that my hard starts are less- well, hard- when I put the key in accessory for a second or so before cranking it. I used to have a diesel F250 and got in that habit, and I did the same with the MJ out of habit a few times. It seems that it starts a little easier.

 

Also, I went through this whole page a while back and founf that in times when I had a hard start (or no-start) situation after weather fluctuations, it helped to clean the CPS contacts.

 

http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm

 

That page is awesome.

[big66440]

It starts up perfectly fine as well as a renix 4.0 goes when the engines at operating temp, I've checked fuel pressure with a gauge and it's perfectly fine,I have new plug wires and a cap I even tried a high performance mallory coil and still no luck,I'm positive the tps is set correctly I used the scanner to set it at .83 volts, I was thinking about replacing the pickup coil in the distributor but see no reason why it would only act up when the engines cold,I've tried priming the system a couple times before i start it and it doesn't help,,,I read somewhere about a tsb were the cps is spliced directly to the ecm has any one heard of this?