D1 Warm engine wont stay running on start

[Busted_D1]

I have done all this trouble shooting so I can list as much information as possible. I hate trying to help when there is a lack of info as much as anyone.

Since the problem started...

When my 96 D1 is cold it starts fine. It does take a couple of extra rotations before it fires up lately.

After driving it for 20 min or so I can shut it off for a couple minutes or so and it will fire right up.

After 15 min of being off, the engine fires right up to 1000 RPM and then starts to sputter and will die within 5 or 6 seconds.

If I hold the pedal to the floor and turn the key, it will start, rev high and run rough as hell for 30 seconds or so then everything goes back to normal.

The engine never stutters or loses power even when climbing a steep grade on the highway, or under low RPM load. I am also in Denver so I will add altitude to the mix.

 

[NikeCheck246]

Sounds like what the fuel rail temperature sensor would cause, but I have never seen a failed fuel rail temperature sensor in person.

 

[Busted_D1]

Glad I put all that into my question. That suggestion is a first for me too. I thought it was a tired fuel pump when this first started but you would think that I would at least one other symptom if that were the case.

I even cleaned up the MAF (as best I could) It gave better response after cleaning it but didn't help the warm start issue.

I have noticed that if I let it sit for an hour or more it starts and doesn?t die, still runs rough for a bit though. Funny how on really cold ass days that time is decreased. When it's warm out it seems to take longer of sitting to get to a normal start sequence.

Anybody else wanna vote for the fuel rail temp sensor?

Maybe a crank position sensor? I've read those can cause this sorta thing too.

 

[Jake1996D1]

Glad I put all that into my question. That suggestion is a first for me too. I thought it was a tired fuel pump when this first started but you would think that I would at least one other symptom if that were the case.

I even cleaned up the MAF (as best I could) It gave better response after cleaning it but didn't help the warm start issue.

I have noticed that if I let it sit for an hour or more it starts and doesn?t die, still runs rough for a bit though. Funny how on really cold ass days that time is decreased. When it's warm out it seems to take longer of sitting to get to a normal start sequence.

Anybody else wanna vote for the fuel rail temp sensor?

Maybe a crank position sensor? I've read those can cause this sorta thing too.

You would most likely be getting codes with a CKPS if it was totally dead your truck wouldnt start

 

[Busted_D1]

I didn't think about that... The only code I get is a 1177 from time to time. I have an O2 that's gonna need to be replaced soon. I only get that one once in a great while.

I'm gonna talk to a guy that has a few D1s as spares. I really hope this is what is going on. Nothing like sitting in front of the local "insert snooty store" and having to crank over your Disco for 5 minutes til it fires.

 

[NikeCheck246]

The Fuel Rail Temp Sensor, according to RAVE, is specifically for helping situations like hot restarts. It is designed to reduce air in the fuel rail(from heat), letting the injectors give a better flow of fuel.

 

[Busted_D1]

Thanks for the help on this. I will post my findings once I replace the fuel rail temp sensor so we don't have another thread that ends with a big ass question mark. :banghead:

 

[p m]

I started getting a similar condition on both of my 96 D1s.

 

[Busted_D1]

OK so I have an update and a question, this one has me dumbfounded. (edit- I didn't change the fuel rail temp sensor yet)

I bought a good quality fuel pressue test gauge just to to see what was going on in the fuel rail. The results are not what I expected.

The gauge, once connected, before starting the engine was zero. The key hasn't been on at all for four days. Once the key was turned it jumped right away to 20 psi. Lower than the 35psi I expected.

The engine was started and the gauge stayed at 20psi (after normal drop in presure during the start). During the warm up process the pressure stayed at a solid 20psi.

Once the engine was warmed up I parked it kept an eye on the gauge expecting it to bleed down. It didn't, it slowly went up and up all the way to 35psi for the 15 min i let it sit. So I let it sit even longer to see what would happen.

After about 25 additional minutes the gauge had dropped back down to 20 psi again. The truck started just fine without any of the hot start issues. It has sat not runnig for almost an hour with no drop below 20psi.

What the hell is going on with this? If I try to start it when the pressure is at 35psi it floods it. If I wait until the pressure goes back down to 20psi it starts great?

 

[Jake1996D1]

Leaky injector flooding it? Or a bad sensor somewhere?

 

[Busted_D1]

Leaky injector flooding it? Or a bad sensor somewhere?

How long should the fuel line hold pressure after being shut down?



The next thing I'm going to try is to release the fuel rail pressure during the day tomorrow when I know it would have the "hot start" problem the worst and see if it starts with no issues. I have a feeling it will fire right up and run without sputtering.

If that works I just have to figure out why this is happening. Using a work around is something we do to get by, not get around town.

 

[KngTgr]

Updates please?

 

[stewcrow]

I'm having the same issues as your describing. When my engine is hot and I shut off the Rover (96, DI), I've learned not to even try to crank it until the engine sits for at least 45 minutes to cool off. If I do try to crank it, it will usually just sputter and die out. Once it cools off, it fires up no problem. I can go short distances and be okay as long as the engine doesn't run too long and get hot.

 

[crown14]

now THIS sounds like an engine wiring harness problem (bad wiring going to the crank sensor)

 

[mr_ed]

Any luck with the temp sensor? This problem matches mine to a tee, and that temp sensor is about the only thing that makes sense that I haven't replaced yet.

 

[Busted_D1]

Any luck with the temp sensor? This problem matches mine to a tee, and that temp sensor is about the only thing that makes sense that I haven't replaced yet.

If you have the same fuel pressure issue I had, replace the fuel pump. The D1 with this problem is now being broken down for a full rebuild and paint. The fuel pump got so bad it would hardly start even when cold. Had to crank the shit out of it just to move it around the shop.

My guess is the problem starts to show up with the hot start and over time affects the cold as well.

My daily D1 had a hot start issue but it was the CKPS. The would also just shut off when at idle.

I hope this helps.