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97 Hummer H1, crank no start..

S

shaun_h1

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Hey fellas, having a weird starting issue and I was recommended to post here. Hopefully you guys can provide some input.

The truck is a 1997 Hummer H1 with the 6.5TD, and DS4 injection pump.

Last week when I went to start the truck, it would crank but not start. I cracked a line at the injectors and fuel came out. I didnt check actual pressure yet because I didnt have a gauge. I checked fuel at the drain valve and confirmed there was no water or contaminants in it.

After 4 or 5 attempts, the truck started and seemed to idle fine around 740 RPM. I noticed that if I revved up the engine all the way in park, it seemed sluggish and only went to 2k (not sure where the rev limiter is set. I noticed my check engine light was on. Scanner read P0251, which is injection pump, rotor/cam circuit malfunction.

I drove it into my garage, turned it off, and it would not restart. After cranking 5 or 6 times, it started, seemed to idle fine, but again would not restart when I turned it off. I threw in a new lift pump and fuel filter but no change.

I was told by a friend that it might be a bad optical sensor or injector pump? Any help or ideas? Thanks in advance.20200222_164737.jpg
 
Last edited by a moderator:
Welcome to The Truck Stop, shaun_h1. Nice H1 that you have, hate that your have problems with it.

Looks like some of these knowledgeable 6.5 guys have offered some suggestions. More suggestions will be posted I am quite sure of that, just be patient.

Will, is one of the Hummer experts on here, I am sure he will chime in soon.
 
So next thing to do is test the OS and the CPS. To do so unplug the CPS and then try to start it, it usually will take extended cranking and when it starts it will be in limp mode. If it doesn't start then the OS or wiring to it is bad, if it doesn't run smoothly without any hiccups etc then same thing. To test the CPS plug it back in and unplug the OS. Results should be the same as when the CPS was unplugged.
 
I unplugged the CPS and it would not start. I also noticed there was no fuel going to the injectors with the CPS unplugged. Replugged it back in and the truck started, but it's doing the same thing it was before. I have no experience or knowledge about the optical sensor, but I'll locate and unplug that when I get home. Thanks.
 
BIGR said:
Welcome to The Truck Stop, shaun_h1. Nice H1 that you have, hate that your have problems with it.

Looks like some of these knowledgeable 6.5 guys have offered some suggestions. More suggestions will be posted I am quite sure of that, just be patient.

Will, is one of the Hummer experts on here, I am sure he will chime in soon.
Click to expand...

Will was the one who sent me here. Thanks
 
I’ve been trying to help him, but got interrupted by an unexpected stay in the hospital- stupid appendix.
I think his os is toast, but not sure what else to check. Thought maybe the os filter if there is one there but he doesn’t see it in the harness. Can anyone post a pic of one in place to show him what heat looking for?

I think he is going to have to get a cko tech2 or software for laptop maybe to setup after changing the os or the entire ip. Whats the current recommendations on those? Didn’t @THEFERMANATOR say a certain one was a good option a while back?

Also at what point does a guy go from just trying a new os to the whole ip? We used to get a lot of miles afterwards, but high mileage in short time trucks.

In the fleet I would swap the parts and we had one guy that loved playing with scanners and computers so when i did the mechanical, he did the clickity click and dialed it in assembly line style. We ate many os sensors with the experimental fuels, and if the new os and fso didn’t fix it, on went a new ip. Driver down time eliminated any extended diagnostics. I fumbled my way through it at the dealership but I as horrible trying to follow step by step instructions. Can’t remember almost any of it. So I am little help with the ds4.
 
Will L. said:
I’ve been trying to help him, but got interrupted by an unexpected stay in the hospital- stupid appendix.
I think his os is toast, but not sure what else to check. Thought maybe the os filter if there is one there but he doesn’t see it in the harness. Can anyone post a pic of one in place to show him what heat looking for?

I think he is going to have to get a cko tech2 or software for laptop maybe to setup after changing the os or the entire ip. Whats the current recommendations on those? Didn’t @THEFERMANATOR say a certain one was a good option a while back?

Also at what point does a guy go from just trying a new os to the whole ip? We used to get a lot of miles afterwards, but high mileage in short time trucks.

In the fleet I would swap the parts and we had one guy that loved playing with scanners and computers so when i did the mechanical, he did the clickity click and dialed it in assembly line style. We ate many os sensors with the experimental fuels, and if the new os and fso didn’t fix it, on went a new ip. Driver down time eliminated any extended diagnostics. I fumbled my way through it at the dealership but I as horrible trying to follow step by step instructions. Can’t remember almost any of it. So I am little help with the ds4.
Click to expand...


Are you ok, Will? I assume you had your appendix, removed? Hope you have a fast recovery.

I had that done at a young age when I was in the 4th grade, they cut me on the right side of my stomach about beltline on me, 5 stiches to sew the area up. Before I got out of the hospital, I got a bad abscess in my throat, maybe it was due to the appendix surgery. Had to stay in the hospital longer and they gave me a liquid medicine that would gag and almost make me throw up. Worst thing was afterwards I had to take it easy for several weeks, no playground rough playing, no heavy lifting, that was tough.
 
If he has a tech 2 or equivalent scanner he could check the closure time. From what I understand it starts out less than 2 but as it wears it goes higher
 
I got this same p0251 clear it and comes back immediately hard starts i was at a idle and it just dyed i thought ok junk acdelco pmd went out pulled in my new flight systems and she started but ses light was on yep p0251 did you ever get it figured out? I made a post on what all mine has done and what ive done.
 
I've been busy with work and havent had a change to troubleshoot anymore. Local reputable diesel shop told me they would swap in a new IP with warranty for $2500. Going back and forth if I should just do that.
 
Ok here is something crazy i had the p0251 yesterday so i unplugged the crank sensor it started took a little longer so i plugged it back in unplugged the os and nothing changed but the p0251 is gone wtf lol maybe i had a bad connection somewhere
 
У меня была такая проблема.
когда разъем оптического датчика был отсоединен, двигатель запускался и работал почти стабильно, но на повышенных оборотах холостого хода около 900.
в конце я немного повернул соленоид на IP (30 грабусов) в сторону пассажира.
Я проехал еще 5 тысяч километров до дома. поворачивая соленоид периодически, когда двигатель начал дрожать.
Тогда я просто вставил новый IP.
 
denata said:
У меня была такая проблема.
когда разъем оптического датчика был отсоединен, двигатель запускался и работал почти стабильно, но на повышенных оборотах холостого хода около 900.
в конце я немного повернул соленоид на IP (30 грабусов) в сторону пассажира.
Я проехал еще 5 тысяч километров до дома. поворачивая соленоид периодически, когда двигатель начал дрожать.
Тогда я просто вставил новый IP.
Click to expand...
Google translate says:

I had such a problem. when the optical sensor connector was disconnected, the engine started and worked almost stably, but at an increased idle speed of about 900. at the end, I turned the solenoid a bit on IP (30 degrees) towards the passenger. I drove another 5 thousand kilometers to the house. turning the solenoid periodically when the engine started to tremble. Then I just inserted a new IP.
 
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