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1989 cold start issues

Posted By: wannadrag

1989 cold start issues - 11/18/17 03:52 AM

89 W250 360 engine,cool weather here,runs very rough on start up till warm almost seems to be running lean as it sputters like not enough fuel,new ignition temp sensor,map sensor and throttle position sensors.Took it to a mechanic and he seems to think ECM, It has a remanufactured mopar one on it with 4557391 part number that when i look it up comes back as a ECM for a 318. When i look up one for a 360 it shows like 3 different ones depending on the factory number which i dont have. Truck has a auto trans and was sold here in the midwest so that would rule out CA emissions type. Any ideas out there?
Posted By: jerseybud

Re: 1989 cold start issues - 11/19/17 04:06 AM

check the fuel pressure
then check the codes

Can almost guarantee its not ECM if it starts. If it took 20 minutes to start and relays were clacking, then maybe ECM. Even a 318 ECM on a 360 should satrt and idle very nicely, just not pull hard.

318 ecm in a 360 is a problem that should be fixed- BUT 89 360 ECMs were a one year only computer (14 pin and 60 pin connectors)
Posted By: SALEM1912

Re: 1989 cold start issues - 11/20/17 07:46 PM

Agree shouldn't be the ecm. Your truck should have air cleaner with the valve to draw warm air from the exhaust manifold when warming up. Make sure it is operating correctly. Also the vacuum hose should have a delay valve in it so it doesn't open on hard accelerate(vacuum drops off) You see in this picture the big tube is missing. Also your egr should not be opening till engine is at operating temp.

Attached picture dodge air cleaner (640x360).jpg
Posted By: Paul_Fancsali

Re: 1989 cold start issues - 11/20/17 07:50 PM

Check the bottom of the coil for rust or leakage I replaced a lot of them way back when
Posted By: buildanother

Re: 1989 cold start issues - 11/20/17 09:51 PM

Also make sure that idle speed motor (seen in above photo) is working. They do a bit of moving at lower speeds, idle and shutdown time.
Posted By: wannadrag

Re: 1989 cold start issues - 11/21/17 05:21 PM

I ordered the correct ECM, should be here in a few days. At least if it still runs crappy I can rule that out and start checking elsewhere for issues.
Posted By: CHRGR69

Re: 1989 cold start issues - 11/25/17 07:36 PM

Runs rough until warm. Sounds like a Mopar to me!
Posted By: SALEM1912

Re: 1989 cold start issues - 11/26/17 04:50 AM

LOL I second that! Started working on Mopars around 1976 just when emissions were new. Seems all we did was cold start concerns. Thank God for FI around '84-'85.
Posted By: wannadrag

Re: 1989 cold start issues - 12/07/17 05:14 AM

Changed out the ECM and still runs like crap when cold. Speeds up and slows down pretty much steady till its warm. Removed the idle speed motor and it still does it. The truck is unmolested so the warm air stuff is all hooked up. Maybe some crap in the throttle body?
Posted By: poorboy

Re: 1989 cold start issues - 12/08/17 04:45 AM

Its got new plugs, plug wires, cap & rotor, and a new air filter, right? lots of people want to jump in on the hard stuff when the problem is often the basic stuff ignored. Gene
Posted By: wannadrag

Re: 1989 cold start issues - 12/09/17 02:58 AM

Originally Posted By poorboy
Its got new plugs, plug wires, cap & rotor, and a new air filter, right? lots of people want to jump in on the hard stuff when the problem is often the basic stuff ignored. Gene
Yup all new, I have a 91 also with a 360 and am thinking of taking the throttle body and trying it on the 89.I just don't get why it idles up and down till its warm. As soon as the temps got in the 40s it stated acting up. I bought the truck this summer so I am sure the issue was there already.
Posted By: SALEM1912

Re: 1989 cold start issues - 12/10/17 09:37 PM

You might check the TPS reading while this is happening .They tend to wear at the idle position. It you see it jumping around while your foot is off the pedal it's bad. Also a lite tap it might show up.
Posted By: 383man

Re: 1989 cold start issues - 12/16/17 05:30 AM

Just curious as when it runs bad cold whats the temp like where you are at when cold ? I ask because I had problems in winter time cold weather in Md where I live whenever it was cold and damp. But mine was a carb on my 318 Ramcharger. My problem was my hot air intake on the air cleaner was not working and after the truck started within a few minutes it started running bad and chugging as I found out the door on the air cleaner was not closing to give me hot air from around the exh manifold and it was still getting the cold damp outside air. What happened was the carb throttle blades were icing up even though it would happen at 30 to 45 degrees. I cant remember but you 89 should be throttle body injection and may still use the heated air intake from the air cleaner. When hot the door stays open and the air in the eng come from the air cleaner snorkel but when colder that door should get vacum to it from a temp sensor in the air cleaner that lets the eng now pull hot air from around the exh manifold shield. And believe me it makes a big difference in the right temp days that can be damp and chilly and the throttle blades can ice up real easy with cold damp air going by them. After I fixed my hot air door I could start my truck and go in the house while it warmed up. Five minutes later it was still running great but when it was not working it would die in about 2 minutes and run bad until the eng and under hood was warm. Dont know if thats your problem but its worth making sure the air cleaner door is working right. Ron
Posted By: 383man

Re: 1989 cold start issues - 12/16/17 05:40 AM

After reading this more it sure sounds like your air cleaner door is not working to give the eng the hotter air from around the exh manifold. Because like you mine would start acting up whenever it got about 40 or below and your eng is throttle body injected so it still has the cold fuel going on the throttle blades like a crab does but a crab wont have fuel hitting the throttle blades at idle. Your Throttle body inj will have a little fuel going by the throttle blades at idle but not alot of fuel. Believe me I was surprised to find out that the throttle blades were actually icing a bit and it fixed mine right up when I fixed the air cleaner hot air door to work. Good luck , Ron
Posted By: wannadrag

Re: 1989 cold start issues - 12/27/17 04:37 PM

Turns out it was the fuel injectors. It was about the only thing left to try. Runs like a champ now.
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