when the truck is being started for the first time of the day taking off i really have to over rev it to keep rpm up high enough to take off. like 2300 so when i let the clutch out the rpm doesnt drop bellow 1000 and bog down horribly. it also backfires and spits when its cold as well. im gonna try disconnecting cold start injector tomorrow morning when i start and drive it to check and see if it has anything to do with morning issues. i can disconnect cold start injector while warm and make no difference across the board on issues. also it has no power on the hills. like having trouble doing 40. even flat city driving it doesnt wanna go anywhere. it idles just fine. cold or not. in the morning if i kick rpm up to 1500 unloaded it surges. while warm it has a real definitive sweet spot at 2100+ that it surges also unloaded. loaded warm i can feel/hear the surging if i am easy on the pedal and can hear over my tires. but it is nowhere near as relevant as it is unloaded. has no codes except if i take rpm to about 1700 it throws a 11. i am worried about having some burnt grounds somewhere though. when i got the truck a few weeks ago there was no battery tie down and the battery jumped over and grounded on the side of the throttle body. so i am hoping i didnt burn out a few smaller grounds somewhere. i did also notice it was hard to time. like the timing mark jumping badly. also reverse lights are inop and switch in trans produces a good ground when it should. bulbs are good and cigarette lighter socket is also inop. all fuses are good.

i have done plugs, coil, wires, fuel filter, timing, adjusted the tps, tested the tps, tested powers and ground at tps and it all seems to check out. little unsure about what i should be getting at the plug though.

next steps i am looking at are replacing distributor pickup. testing fuel pressure at the rail. replacing 02. compression and valve adjustment is good.

i need specs for tps testing at sensor its self, sensor setting procedure to be sure, plug voltages/resistances and pin locations at ecm. i really dont know where else to go with this issue so i mean any expertise, personal experiences or suggestions are hugely welcome. and any info possible for other issues(not main concern atm).

im new to the form but am usually the go to guy of my friends. i am a diesel tech at a volvo mack truck dealer and im usually pretty good with most everything compared to what im used to and this 1 is a pain without proper references lol. so i look forward to seeing what everyone has to say

 

anyone have any ideal? i hate to be replacing parts i do not need to replace.

 

Have you checked the intake routing and throttle plate for gunk buildup, and is the throttle and idle air bypass adjusted properly? Have you checked for codes? Clean VAFM with MAF cleaner It maybe sticking. You can use MAF cleaner on the O2 sensor safely.

 

take your maf sensor apart and clean it.

 

also what has started this issue? water or what? does the ck eng light come on?

 

sounds to me like a wiring issue from the battery grounding out on the throttle body. get a wiring diagram and check fusible links and grounds.

 

no gunk build up. its still a relatively fresh engine. only about 30k. for 16 bucks i figured i would just replace o2. but i haven't gotten that far yet. i will check MAF and clean as well. light does not come on no. but if i pull codes it will just flash the 1 time repeatedly showing nothing is wrong. till i kick rpm up to about 1700 and then it will flash a code 11. i have a coworker who has all data pro at home who is printing out some info for me. so we will see. it was apparent to me before but not to the same degree. did a full ignition system tune up on it and drove it around and all the sudden it started to have worse bogging issues. but there were a few times i drove it that it felt like it should then it just started running badly. i went back over everything i did and there is nothing i did to make something worse. i am seriously thing pickup or ignition module. obviously i have a tps issue somewhere still but it had been there. i figured out other electrical issues. one was someone rewired the cigarette straight to the battery and it wasnt hooked up. need to add a fuse though and the reverse lights was a wire pulled away from the pin by the starter but not out of the plug. so all that is good its just this frustrating running issue.

 

thank you for replies. you have me thinking more

 

Do you have any white smoke coming out of the exhaust? Sounds like to me you might have the beginnings of a blown head gasket, especially since you have no power in the truck. You can buy a tester kit for $40-50 bucks. Either that or a fuel pressure issue or leak.

 

nope compression is good all cross the board.. no smoke. how can i check pressure in the rail? and what should specs be from pump and at rail? noticed that while timing while possibly a bad timing light time jumps around. pickup tests good. is there a way to check ignition module?