Possible FI problem

[Ben Drinkin]

Let me pick your brains. Got a fuel injected 4 cylinder, about 2001 model.. (obviously not an A body). At normal temp, runs fantastic. Starts easy enough, but until it gets warm, you can hardly do anything without it wanting to die. Computer shows no codes as a clue to what's amiss. The engine is in Caterpillar forklift. Any basic stuff i could check out? Our Caterpillar guy can't seem to make it right. They've put in a new fuel pump.. new spark plugs (cuz the last genius 'knew' that was the problem. Thay looked great to me).. ran a couple cans of Seafoam though it with the last 2 tanks of gas, no noticeable difference. Is there a sensor that may impact this? I'm afraid they're gonna want to throw injectors in it and I'm not 100% convinced that's the problem. Any ideas would be appreciated..

 

[spl440]

Temp sensor?

 

[Ben Drinkin]

Temp sensor?

Thanks. I'll make that my first inspection. I have no experience with forklift engines, but it is just a gas engine. Can't see paying these guys 100 bucks an hour to guess.. i can do that just fine.. and I'm guessing i can source internet parts for a fraction of what they're sticking me for..

 

[spl440]

Thanks. I'll make that my first inspection. I have no experience with forklift engines, but it is just a gas engine. Can't see paying these guys 100 bucks an hour to guess.. i can do that just fine.. and I'm guessing i can source internet parts for a fraction of what they're sticking me for..

Yes, with no codes it can be difficult, and I am no a FI guru either. But first reaction was a difference between cold running and warmed running, so check sensor to see what the output is between cold/warm. Could also be restricted fuel filter, giving enough fuel when warm, but not enough when cold and needing to run richer

 

[Ben Drinkin]

Yes, with no codes it can be difficult, and I am no a FI guru either. But first reaction was a difference between cold running and warmed running, so check sensor to see what the output is between cold/warm.

I appreciate the input. Makes good sense.

 

[dano]

Does it have an oxygen sensor? Does it run off a hot wire type mass air meter or is is speed density? EFi uses a lot of eyes and ears to run properly. Running good cold tels me it a sensor issue when it gets warm. As said above, a watercoolant temp sensor could be faulty causing it to run rich as this tells the ECU "hey I'm warm, cut back the fuel".

 

[Ben Drinkin]

Does it have an oxygen sensor? Does it run off a hot wire type mass air meter or is is speed density? EFi uses a lot of eyes and ears to run properly. Running good cold tels me it a sensor issue when it gets warm. As said above, a watercoolant temp sensor could be faulty causing it to run rich as this tells the ECU "hey I'm warm, cut back the fuel".

I haven't looked at it much yet. Just sick of paying for less than acceptable work. Thanks for your input. I'll look into item you mention. Seems odd it throws no codes. I figured if a sensor was out, it'd code that.. I'm guessing the ecu (if that's what it's called) is very basic on this unit.. when warm, she runs great. Just seems like she gets no fuel when less than operating temp..

 

[Lustle]

I haven't looked at it much yet. Just sick of paying for less than acceptable work. Thanks for your input. I'll look into item you mention. Seems odd it throws no codes. I figured if a sensor was out, it'd code that.. I'm guessing the ecu (if that's what it's called) is very basic on this unit.. when warm, she runs great. Just seems like she gets no fuel when less than operating temp..

I know that sometimes things like the MAF or what not will not be working properly. But not throw a code. Had that problem on my old truck. When it was cold and in gear it would occasionally idle low and vibrate bad. Or it would start to "hunt" the tach, where it would drop really low then up, then low, then up. A cleaning of the MAF and throttle body sorted that out. I'm thinking you might have a similar condition where the MAF (or other sensor maybe) isn't sending right and when you put load on the engine when cold, it doesn't appropriately raise RPM, either by adjusting fuel or air intake, to compensate and stalls out.

IF that makes sense.

 

[Ben Drinkin]

I know that sometimes things like the MAF or what not will not be working properly. But not throw a code. Had that problem on my old truck. When it was cold and in gear it would occasionally idle low and vibrate bad. Or it would start to "hunt" the tach, where it would drop really low then up, then low, then up. A cleaning of the MAF and throttle body sorted that out. I'm thinking you might have a similar condition where the MAF (or other sensor maybe) isn't sending right and when you put load on the engine when cold, it doesn't appropriately raise RPM, either by adjusting fuel or air intake, to compensate and stalls out.

IF that makes sense.

Does make sense. Thank you. Maybe simply cleaning a few a sensors. Low hanging fruit.. I'll check it out..

 

[Turbo poly]

May not help , I had a similar issue with my 300zxTT , Turned out to be the EGR system was bad , this system does not work until engine is warm , put a ball bearing in the the hose going to the actuator . That is of coarse providing the forklift actually has any of this stuff on it ?
Failing that check thermal vacuum switches .. Good luck

 

[Ben Drinkin]

May not help , I had a similar issue with my 300zxTT , Turned out to be the EGR system was bad , this system does not work until engine is warm , put a ball bearing in the the hose going to the actuator . That is of coarse providing the forklift actually has any of this stuff on it ?
Failing that check thermal vacuum switches .. Good luck

More ideas. Thanks.. I'll bet one of these should get it. Thanks for all the input.

 

[Syleng1]

1)Is the unit propane or gasoline? What model?
2) have you checked the hydraulic pump relief valve (electric)- those open electrically to allow the cold hydraulic oil back to the tank to have less resistance on the engine when cold. If stuck shut it puts a hell of a drag on the engine especially cold (below operating temp) That model may or maynot have one it is typically on the pump or on the main large valve bank.
3) if Gasoline are you sure the fuel is good? Most pump fuels are only good for 30 days before they start to turn to crap. Filters wont fix that issue. if propane- are you sure your getting enough pressure - regulators go bad.
4) crankshaft pick up sensor goes bad on those gas or propane. I'm not sure if your ins in the block or the distributor.
5) How old is this unit? If propane- diaphragms go bad on the regulators and the unit that replaces the carburetor. when it acts pokey- try spraying brake cleaner into the intake hose before the airfilter (as long as it is not diesel.... I know you said spark plugs but more than one person told me sparkplugs on heavy equipment and ment glow plugs. see if riching up the air / fuel mixture helps with running. You may have a bad air leak.
6) if really new machine its all electronic control. all you can check is the basics like plugs, cap/ rotor, vacuum readings and basic timing.

Good luck.
Joe