Stutter at idle
03-11-2018, 01:03 PM
#1
Stutter at idle
I have a 99 that is stock auto (213,000). that is stuttering/missing at idle in park and neutral. Once in gear it goes away but happens a little when coming to a stop but then fine once stopped and in gear. Drives fine on the hwy, shifts good and plenty of power. Did the APPS reset, changed the fuel filter. Doesn't get driven daily unfortunately. I guess disconnect both cables at the alternator to see if that is the culprit? Or bad injector?
Thank you for the help hope this doesn't sound too stupid
Hutch
Edit: No check engine light and no codes with the autozone code reader
Thank you for the help hope this doesn't sound too stupid
Hutch
Edit: No check engine light and no codes with the autozone code reader
Last edited by hutch98; 03-11-2018 at 01:11 PM. Reason: add more info
03-11-2018, 03:46 PM
#2
Registered User
Basically this sounds like either a bad injector or not enough valve clearance on at least one cylinder to me.
I'd start with checking the valve clearance, if that's OK with a known good diesel cleaning additive.
If that does not help, I'd get the injectors checked at a shop, and also check the crossover tubes before reinstalling the injectors with new copper washers and O-rings.
(Or get some aftermarket injectors if yours are found bad, I do really like the Mach series from F1 Diesel)
I'd start with checking the valve clearance, if that's OK with a known good diesel cleaning additive.
If that does not help, I'd get the injectors checked at a shop, and also check the crossover tubes before reinstalling the injectors with new copper washers and O-rings.
(Or get some aftermarket injectors if yours are found bad, I do really like the Mach series from F1 Diesel)
04-15-2018, 08:54 PM
#3
Registered User
My truck is a manual transmission, but I had a shudder at idle that was corrected when I replaced the fuel injectors.
It felt almost like a "miss" as compared to an older gas engine. And it only happened at idle after warm; like when if I had been driving for awhile and then came to a red light. It did not have any noticeable power loss and was not throwing any codes.
Checking valve clearance is a good idea too. I check mine every 100,000 miles.
Are you running the factory-original injectors? if so, that would be my bet as to what is the problem based on your mileage. One of more of them is getting "sticky" and doesn't release at the designed pop-pressure; only happens at idle (I think) because once the RPMs come up the fuel pressure overcomes the force making them stick, or the revolutions happen fast enough that it is not perceptible.
Lots of options for injectors out there. Alpine's recommendations are good. I ended up going with Bosch RV-275 injectors (stock for this engine but in motor-homes, slightly higher HP rated). They are a very affordable option for a mild performance upgrade (40 HP upgrade). I bought them from Piers Diesel: PDR Diesel 275 RV 40HP Injector
It is really not a bad job to change them, and while you are there it is also the perfect time to check that valve clearance.
It felt almost like a "miss" as compared to an older gas engine. And it only happened at idle after warm; like when if I had been driving for awhile and then came to a red light. It did not have any noticeable power loss and was not throwing any codes.
Checking valve clearance is a good idea too. I check mine every 100,000 miles.
Are you running the factory-original injectors? if so, that would be my bet as to what is the problem based on your mileage. One of more of them is getting "sticky" and doesn't release at the designed pop-pressure; only happens at idle (I think) because once the RPMs come up the fuel pressure overcomes the force making them stick, or the revolutions happen fast enough that it is not perceptible.
Lots of options for injectors out there. Alpine's recommendations are good. I ended up going with Bosch RV-275 injectors (stock for this engine but in motor-homes, slightly higher HP rated). They are a very affordable option for a mild performance upgrade (40 HP upgrade). I bought them from Piers Diesel: PDR Diesel 275 RV 40HP Injector
It is really not a bad job to change them, and while you are there it is also the perfect time to check that valve clearance.
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