ok so over time it went away, now after my distributor cap/ rotor, cam sensor (all ac delco) and camshaft sensor (bwd) was replaced, my hard starts got worse. fuel test via captains sticky Pass with pressure and leakdown from both fuel filter then shrader valve.

my problem is, after sitting overnight, i start the truck, idles at 1000, quickly drops to 500, acting as if its going to stall and rumbles hard, then the engine revs itself (still in park) to 1500..and rounds off at 1000 after its done doing that.

then drives perfectly fine. ive been getting better mpg since the distributor cap and rotor has been switched (18-20mpg) where as before it was 15-18 avg

i cant figure out why this happens. throttle body was recently cleaned. very dirty around the edge of the plate, and iac pintle was cleaned thoroughly. also iac was replaced with ac delco.

ANY help is greatly appreciated.

also i checked with soapy water around all vacuums lines, didnt miss a beat, so i dont suspect a vac leak. granted i replaced most of the rotting lines (that i found) last year and they still look in great shape

 

Have you compared ECT, IAT and ambient temperature on a stone cold engine? Don't start the engine for the comparison, key on, engine off. All three should be within a couple of degrees of each other.


Have you checked/adjusted camshaft retard?


Does the check engine light come on with the bulb check, and then turn off?


Is the check engine light on after the engine is running? If so, what codes are present?

 

all 3 are withing a degree of eachother so thats good.

i have not checked camshaft retard, im not exactly sure how to

cel comes on with bulb check and then does turn off, no codes are stored in the memory so nothings "pending"

 

Camshaft retard aligns the camshaft position sensor with the camshaft, while at the same time, aligns the rotor segment with the cap terminals. This reduces the possibility of crossfire inside the cap. It is checked using a scan tool capable of accessing the data stream, (not all scan tools can access it). The adjustment is made by slightly rotating the distributor. It does NOT affect ignition timing. From the factory, the adjustment will allow for approximately 10 degrees total. If proper adjustment can not be achieved, the distributor hold down must be modified. Spec is zero degrees plus or minus 2 degrees. If camshaft retard is less than ~27 degrees off, advanced or retarded, no DTC will be set, but rest assured, there will be crossfire inside the cap, and it may or may not set a misfire code.

 

i doubt my innova 3160d will be able to access that. i may have to bite the bullet and take it to a "trusted" mechanic, aka not the one who did this dist cap, rotor and cam sensor. maybe you can clarify this, i know theres a crank relearn. is there also a cam relearn?

 

There is no "relearn" for camshaft retard. It is adjusted manually by rotating the distributor. It's part of the job when reinstalling the distributor, just like setting the timing on a conventional engine was. On either style of engine, if it's not done, you will have performance problems.


The PCM uses camshaft retard data, along with crankshaft position sensor data, to detect and accurately identify cylinder misfire. If either are incorrect, misfire identification will be incorrect, which will send you on a wild goose chase trying to figure out a misfire.


If the crankshaft position sensor and or timing cover are moved, removed, replaced, or disturbed in any way, performing a crankshaft position sensor relearn is mandatory. The same holds true if the PCM is replaced, because relearn data in the replacement PCM retains relearn data from the last relearn, which is incorrect for the engine you just installed it on. If it is not performed, the engine will still start and run, but ignition timing and injector timing will not be correct. If you're unsure if a relearn has ever been done on your vehicle, having it done might improve performance and fuel mileage. Checking and adjusting camshaft retard at the same time is a good idea. Camshaft retard and the crankshaft position sensor relearn are both done with a capable scan tool. For the relearn, once the vehicle is programmed into the scan tool, engine speed is brought to 4K rpm in neutral. The PCM will then take over throttle control and bring it back to idle. DONE. Literally takes less than 3 seconds.


No DTC will be set telling you that the crankshaft position sensor relearn data is incorrect, unless the relearn fails during the procedure. Incorrect camshaft retard will not set a DTC (P1345) unless it's off by more than ~27 degrees. The most common reason that P1345 is set is due to incorrect distributor installation, (off at least one tooth).


Note: The camshaft position sensor can not cause a no-start condition, (it does not control or affect ignition spark). You can unplug it and the engine will still start and run, but without misfire detection, and it will set a DTC.

 

so im starting to think that the place i brought it to (meineke) to do all the work (cap, rotor, cam and crank sensor) never did the relearn at all...from seeing all the posts on here that a relearn must be done, i brought it to the shop owners attention (after it ran like crap and had him take out the junk aftermarket parts and put in the cap and rotor i originally asked for ac delco) he told me it wasnt necessary . red flag there, but when i got it back he said he did it, which i highly doubt he did.

so i should have my mechanic do a camshaft retard and crank position sensor relearn? i know hes got the right scanner for it, he was all excited to use it and was showing me lol. it should also be able to tell the camshaft retard degrees?

 

About the only way you'll be able to tell if he put AC Delco on, is get the AC parts and compare them side by side.


Sounds like a questionable shop, so you might want to have a reputable one check, and adjust if necessary, camshaft retard and do the crankshaft relearn, then you know for sure that it's done. If the shop has nothing to hide, and are truly concerned about satisfying you, they'll let you watch. The old line, "our insurance won't allow it" is BS. I actually encourage it, been in the business 40+ years and never had an issue.

 

i know the cap is delco. ac actually has the numbers on the cap whereas the junk he first put in didnt. i was trying to compare the cam sensor with the one he took out, i know the ac delco doesnt say made in america on it like the one he had originally put in, and from what i could tell i couldnt find it on the sensor after the 2nd visit.havent checked rotor.

i originally told him ALL ac delco parts when he told me what had to be replaced. and he went against everything i said. for the price, i wouldve brought it to GM and know things wouldve been done right.

its an expensive lesson that ill definitely learn from. going to take it to my mechanic monday. ive been living with my girl which is why i gave meineke a chance...next time ill use my aaa and get it towed to where itll be done right.

ill keep you posted if the the crank relearn and camshaft retard make the difference

 

i took it to my guy, he let me sit in the car, crank relearn was sucessfully complete. even let me see the scanner as he took 5 seconds to do it. all the steps he did were exactly as you said captain.

so now i know officially its been done, ill let it sit overnight from a cold start and let you know if that was the issue