big problems

[Holty]

Yesterday i changed my belt from the stock 112" that comes with the Radix kit to a 110.5" Goodyear Gatorback. The steps i took to replace the belt are as follows: removed the air intake tube from the MAF to the Throttle body, then removed the top radiator shroud and then loosed the tensioner, then removed the belt. I then installed the new belt adjusted the tensioner, put the intake tube and radiator shroud back on. Started the truck, runs and idles good, did not immdialetly test drive it though. Went outside through the football around a little with some friends, then my buddy came over to show off his newly painted MR2. We then decided to go to Wendy's, hopped in the truck, and took off down the road.

 

Here's the issue, the truck starts, idles, and drives fine, UNTIL you try to put the truck under some significant load. Once you start to get into it, making about 5psi of boost, the engine starts to shutter/miss/vibrate/shake really bad, and the power seems to be missing as well. If you continue to stay in it, it will make boost fine, up to about 9psi, but the engine is shuttering/vibrating violently, but does continue to run. I let off the pedal immediatly, and the truck continues to run fine again. Now i'm like WTF!!!???

 

So, took the truck home pulled it in the garage and opened the hood, can't see ANYTHING out of the norm. First thing that came to everyones mind (since we had the intake off changing the belt) is a vacuum leak. So i took the intake back off, checked the line going from the intake tube to the intake, it is on good. Put the intake tube back on good and tight, took it for a test drive, still doing it.

 

Brought it back home, (really getting worried now), and starting back tracking all my steps on changing the belt.

 

Now, keep in mind, the truck ran fine all day prior to installing the new belt. This all started happening AFTER i changed the belt.

 

Figured, OK, maybe its the belt causing something crazy to happen, slipping of something (not likely at all, but i don't know what else to check at this point). So i took everything back apart, put the original 112" belt back on, and its still doing it. Took everything back apart AGAIN, and put the Gatorback on again. This time being VERY VERY attentive to EVERYTHING we were doing, making sure EVERYHTIHG is tight, etc. Still doing it

 

Next we start checking all other hoses, connections, etc. Checked all the spark plug wires, injector hookups, re-torqued the intake manifold (lol), pcv valve, MAF (took it off, verified all is good). I mean we stared at this engine bay for like 3 hours checking and rechecking everything we could get our hands on. Also, not getting ANY CEL's.

 

Now, about pissing my pants, i call up Bill (wkdivr), he comes over, hooks up his HPTuners to see if we can see any codes that might not have tripped the CEL. Not seeing any however. Started the truck with HPTuners logging on, and held the brake down, put it in Drive, then gave it gas until I could make the engine shutter. Then we looked the HPTuners log and compared it to one we did for my truck a few weeks ago. The only abnormal thing we were seeing is that the timing is all over the place. It dosn't look normal at all. I'll let Bill chime in and give more detail on that one. After seeing this, we decide to reprogram the pcm using the stock Radix tune (which is what has been in there working fine since the Radix install). PCM re-tune was successful, however that did not fix it.

 

Now we're at a loss, can't figure this out for the life of me. I'm sure that it's hard to completely understand the description of the problem from just reading what i've typed so far. The best way for me to explain it is to say it sounds/feels like maybe i'm dropping a cylinder or maybe two. Bill thinks it sounds/feels like i'm hitting my rev limiter. I hope that might help you guys better understand my problem.

 

Anybody have any ideas? i'll probably have to take it to my mechanic tomorrow to see what he thinks.

 

Bill, if i missed anything or you can elaborate more on this, please chime in.

[orlando]

I whould rule out the spark plugs and wires also before takeing it in.

[Justin Lamanna]

if your free this week during work i could take a look if you want. most likely it is because of the pcm reprogramming. let me know

[Holty]

pmc tuning? what makes you think that? not second guessing you, just curious?

 

i'll be at work tomorrow, i'll give you a call on my lunch break, but i'm not driving my truck until i figure this out.

 

On a side note, i took my neighbor for a ride in the truck today. I just asked him to go for a ride and didn't tell him any of the details, just that something was wrong. His first impression was that the torque converter seemed to be engaging/dis-engaging, engaging/dis-engaging. What do you think Bill, a possiblity?

[PladdPezzPunk]

sounds like you may have bumped the MAF the wrong way. I would check the the real time data to see if you have a big fluctuation of airflow (g/in3) when it starts to bog down/skip. it should move real smooth with engine rpm chances are by moving what you did, you couldn't have a bad plug or wire, unless you touched one of those.

 

just my thoughts, hope this helps

[BenKey]

It seems kind of hard to believe that just a belt change did this. I would note that it not necessary to remove anything to get your belt off. Even the tensioner. It's a 3-minute change without removing anything. You put a socket on the tensioner nut and push it down to relieve tension on the belt. I've never seen it, but wonder if it would act that way if the belt was too loose. Are you sure the tensioner is back on right and the belt is really tight? Not sure the MAF would do that, unless you put it in backwards, maybe.

 

Sounds like misifre to me. But if it was that bad, you'd have a blinking SES light.

[mwalls54]

is the MAF plugged in???

[budhayes3]

Since it happend after changing the belt, and all that you really removed was the air intake tube, I'd be thinking that maybe some junk got on the MAF or something along those lines. You could try cleaning the MAF, or swapping another one in if you have a friend with the same part that you could borrow.

[Holty]

found out that it is a misfire, finally got the CEL to come on and flashing. gonna change and plugs and wires tomorrow.

[BenKey]

found out that it is a misfire, finally got the CEL to come on and flashing.  gonna change and plugs and wires tomorrow.

<{POST_SNAPBACK}>

Did you happen to disconnect the main wiring for the coils? One on each side.

 

Make sure a individual coil pack connector has not come out somehow.

 

Plugs - one click to get on right; Coils - two clicks, audible

 

Pull your plugs and make sure one, or more is not cracked.

 

Sounds to me like you have one of your main connectors left off.

 

Changing plugs will not fix, unless you have somehow cracked one or more. Your problem is in your wiring, if I had to guess. Only speaking from experience. I've done it all - left off one side (main connector), cracked two plugs, had plug wires come off, etc..

[Justin Lamanna]

Make sure the plug wires aren't touching anything metal as well.

[PladdPezzPunk]

don't forget that all of that will immidiatly triger a check engine light. If a coil is unpluged the computer dosen't sense the resistence so trigers a light, if the skip was from a plug the crank sensor would pick up on the variance and trigger a light, it sounds more like the engine is bogging down, either rich, or lean, than actually skipping.

[PladdPezzPunk]

sorry, i missed part of the thread, i'm a moron. disreguard the last comment

[Holty]

UPDATE

 

drove up to Summit Racing today with good 'ol Bill (wkdivr) and picked up a set of MSD plug wires. Came home and swapped the plugs for a set of NGK-TR6's and put the MSD wires on, no more misfire.

[PladdPezzPunk]

glad to see it all worked out