RPM stuck after maintenence, HELP

[JBR8517]

Having some pretty serious sounding troubles with my NA 1.6. The motor has about 5K on it and was never retorqued (after warm), not sure as to why but it was emphasized.

Due to attempts to solve a bad oil leak I have just recently changed the  front main seal and intermediate shaft seal, retimed the motor afterward (for accuracy) and replaced the injectors (very old) with some Bosch rebuilt ones. Also timed the pump to 0.95 mm.

 After talking to a few motor-savy friends and running the engine until warm I decided to retorque the head bolts just 1/4 turn and perform a compression test.

Just finished all of this and the motor has suddenly began to run horribly. A terrible vibration at idle and above, and the biggest concern is when the throttle is increased the RPMs stick then slowly (over several seconds) returns to idle despite the throttle having returned to idle as soon as released. Also just before reaching idle the motor shakes violently as if something is unbalanced.

Anyone ever experienced this or know whats going on? All the cylinders are getting fuel. I'm at a loss and have cut myself close as I have to return to school (500 miles) tomorrow.  :x

[Rabbit TD]

Having some pretty serious sounding troubles with my NA 1.6. The motor has about 5K on it and was never retorqued (after warm), not sure as to why but it was emphasized.

Due to attempts to solve a bad oil leak I have just recently changed the  front main seal and intermediate shaft seal, retimed the motor afterward (for accuracy) and replaced the injectors (very old) with some Bosch rebuilt ones. Also timed the pump to 0.95 mm.

 After talking to a few motor-savy friends and running the engine until warm I decided to retorque the head bolts just 1/4 turn and perform a compression test.

Just finished all of this and the motor has suddenly began to run horribly. A terrible vibration at idle and above, and the biggest concern is when the throttle is increased the RPMs stick then slowly (over several seconds) returns to idle despite the throttle having returned to idle as soon as released. Also just before reaching idle the motor shakes violently as if something is unbalanced.

Anyone ever experienced this or know whats going on? All the cylinders are getting fuel. I'm at a loss and have cut myself close as I have to return to school (500 miles) tomorrow.  :x

Are you saying it was running ok up to the point when you retorqued the head or was rough after the seal replacement?  More than likely it's out of time if it was right after the seal change maby off a tooth ?  But if it just did it after the retorque I couldn't begin to guess unless one of those stretch bolts snapped afterwards, I hate those things.  It sounds like a timing issue to me though, make sure you are not a tooth off and recheck at the pump what the indicator says, possibly the pump wasn't tightened enough and it slipped a little.  I would put a wratchet on the crank pulley before I did anything and turn it over a couple turns and make sure the pistons are not hitting the valves.  I hope you find it and it's not a major problem.

[fatmobile]

The rpm hang makes me think an injector might be spraying funny.

[JBR8517]

I performed the seal replacement, timed the engine and pump, then installed the new injectors. At that time it sounded great, but I desired a warm compression test and wanted to get it warm to retorque.

I'm hoping the pump slipped and will check that in a few minutes. I'll crank the motor by hand at that time.

Compression numbers:
Cold and pre-REtorque
 Cyl. 1 - 375
 Cyl. 2 - 400
 Cyl. 3 - 325
 Cyl. 4 - 320

Warm and retorqued
 Cyl. 1 - 410
 Cyl. 2 - 400
 Cyl. 3 - 375
 Cyl. 4 - 400

[JBR8517]

Well I have presented this on another preexisting thread here is an update.

Ok here's what I have after a lengthy yet enjoyable reading session of my bentley. Blue smoke at cold startup is a tell tale sign of injector trouble, any other situation is usually oil consumption but I think this time I'm lucky.

IP Timing is 0.95 mm right where I left it. I timed it with the cold start in, so no worries there. When cranking by hand I hear no contact between valves and piston, and no seizing or any other issue.

What I think may have something to do with it:
When installing the injectors I had trouble getting my deep socket to seat fully on the injector lower body, thus I gave each a little hammer tap. I noticed that after doing this my line nuts were rather difficult to thread on to the upper body. Spare me the lecture on that one as I know my mistake and its consequences now.

Solution:
Remove the injectors and inspect. Once apart can I assume that when reassembled and torqued to spec there is no disruption to the calibration? If there is any thread damage to the upper injector body at the line end, can I use the upper body from my original injectors with the internals and lower from the new. Also can I yet again assume the calibration to be fine with my hybrid new/old injectors if using all new internals and lower?

Looks like fatmobile may have had it all along. I'll be giving this a shot in the AM.


Thanks for the help so far, looks like I'm calling it a night for now.

[burn_your_money]

I'd start by swapping in the old injectors and seeing if it improves. Does it smoke?

[JBR8517]

Well I pulled each injector (this time with a properly clearanced socket) cleaned and deburred the threads. Then re-installed and torqued to spec. Fired up and she roared to life. Once warm there was no more smoke and all cylinders sounded very smooth and linear.

Thanks for the help!