Hard start when the engine is hot

[groovemonster]

I Just replaced the entire fuel system in my 86 IDIT. Lift pump, IP, injectors, glow plugs and harness, and all new fuel lines on the engine. When cold (first start of the day) it fires immediately and idles well. But once the engine is up to temp and I try to start it, the engine cranks for 30+ seconds before it fires up. I have only about 300 miles on the new parts. Where should I start looking?

Please advise...

 

[chillman88]

Where did the new IP and injectors come from?

 

[Philip1]

I know you said the ip is new however I would check it by pouring cool water on the ip when it struggles to start and see if that made a difference. If it does its likely you might have a dud of an ip.

 

[hesutton]

Where did the new IP and injectors come from?

Excellent question. Not all rebuilds are quality work for sure.

I know you said the ip is new however I would check it by pouring cool water on the ip when it struggles to start and see if that made a difference. If it does its likely you might have a dud of an ip.

First thing I thought was heat soak too. If you pour cool water on the IP when it is hot and it starts easily, your IP isn't properly rebuilt and needs replacement. With heat, the tolerances are too large for adequate function of the IP. When you cool it, the tolerances tighten up and it will start.

Heath

 

[renjaminfrankln]

I Just replaced the entire fuel system in my 86 IDIT. Lift pump, IP, injectors, glow plugs and harness, and all new fuel lines on the engine. When cold (first start of the day) it fires immediately and idles well. But once the engine is up to temp and I try to start it, the engine cranks for 30+ seconds before it fires up. I have only about 300 miles on the new parts. Where should I start looking?

Please advise...

As already mentioned, this is a symptom of a worn out IP. The cheap rebuilds you can find - they just clean the cores up and reseal them, you are rolling the dice if you are going to get a good pump or not. Have you already sent in your core?

Before searching reviews I bought one from Pensacola and it was DOA. The good news is they will exchange it no questions asked. I ended up with a 90cc pump from Classic Diesel Designs.

 

[MtnHaul]

When your engine starts in the morning does it run fine for as long as you need it and the problem ONLY appears after you shut it off? I ask because a guy I know had an issue with a chipper that looked like an IP problem but turned out to be the fuel system was drawing a vacuum in the tank. Much cheaper fix than an IP.

 

[hacked89]

Have to ask, why did you replace the entire fuel system? What issues existed before the replacements? Was the hot start one of the issues before you went and replaced everything? Or only after?

Sent from my SM-G955U using Tapatalk

 

[riphip]

When your engine starts in the morning does it run fine for as long as you need it and the problem ONLY appears after you shut it off? I ask because a guy I know had an issue with a chipper that looked like an IP problem but turned out to be the fuel system was drawing a vacuum in the tank. Much cheaper fix than an IP.

Not on a '86 from my experiences. Maybe on late models

 

[IDIBRONCO]

My first thought was heat soak in the IP as well. So I'm going to try going outside the box just to be different. I'm going to give the new IP and injectors the benefit of the doubt for now. Try advancing the timing. Maybe, during the first, cold start, the timing advance being engaged could advance the timing enough for it to start easily. Then, when the engine is hot, there is no outside timing advance and the engine won't start easily. I hope this was far enough outside the box for at least a few chuckles.

 

[dgr]

My first thought was heat soak in the IP as well. So I'm going to try going outside the box just to be different. I'm going to give the new IP and injectors the benefit of the doubt for now. Try advancing the timing. Maybe, during the first, cold start, the timing advance being engaged could advance the timing enough for it to start easily. Then, when the engine is hot, there is no outside timing advance and the engine won't start easily. I hope this was far enough outside the box for at least a few chuckles.

Try energizing the cold advance to quickly test this theory.

 

[IDIBRONCO]

So easy I should have thought about it myself.

 

[groovemonster]

Thanks for the input, I apologize I have been slow in responding. But to answer a few posts....

First, I will try the heat sink trick and see if it works
I purchased the IP and injectors from Pensacola Diesel. Unfortunately, I did not know about their reputation prior to the purchase as this my first IDI. I know it's under warranty but I sure don't want to have to do the work all over again. But the heat sink will reveal the truth.

@IDIBRONCO, your timing suggestion might not be to crazy. I had to advance the timing quite a bit as it ran really rough and smoked like crazy when it fired up after the install. If the heat sink doesn't reveal a problem I will go to timing.

@hacked89, great question. I replaced the entire system because it was all original to the truck. Dinah, [that's what I named the truck], came home on a wrecker back in February with total IP failure. So I replaced every component and when I removed the old stuff it was all dated 12/85, indicating the FI, IP, and return system were original to my 86!

While I was under the hood, I replaced the entire cooling system, all the belt driven components, all new belts and hoses, and did some trans maintenance. I have rebuilding the and converting the A/C system, new brakes, new wiper motor, and new radio on my short list of upcoming repairs and improvements.

I will keep y'all posted on the heat sink results

 

[renjaminfrankln]

I know it's under warranty but I sure don't want to have to do the work all over again. But the heat sink will reveal the truth.

I pulled and replaced my IP twice before I finally bit the bullet and bought a rebuild from CDD. So that makes 3x replacements.

Then I found a bad exhaust valve (#1) and had to tear the whole thing down!

 

[IDIBRONCO]

I purchased the IP and injectors from Pensacola Diesel. Unfortunately, I did not know about their reputation prior to the purchase as this my first IDI.

After seeing this, I would like to withdraw my timing suggestion. I would suspect the IP and injectors first. The only thing that I bought from them was a return line kit. That worked fine until I pulled the engine to overhaul it and bought another one from Mel.

 

[IDIBRONCO]

Unfortunately, I did not know about their reputation prior to the purchase as this my first IDI.

This sucks, but don't feel too bad. Most of us have made similar mistakes. It's an expensive learning curve.