1g NT suddenly stopped running well

[jdhutchin]

I started my car to go home from work today, and it didn't run right. If you let it idle, it stumbles to around 400 rpm for a second or two, then dies. If you give it gas, it will run, but it's rough and kinda stutters a little. Despite this, I was able to get home (although I had to re-start it after every stoplight). Going to work this morning, I didn't have any problems or any sign of any problems.

When I got back, I tried a couple of tests. I backed the BISS out all the way- made no difference (would have expected an idle surge if this was the problem). Compression was consistently ~180-180-180-160. I checked the resistance of all the spark plug wires, and they seemed a little high, but within reasonable values (5000-9000ohms) compared to what I've seen on some other threads. I pulled all the plugs, they looked fine. Then, I checked that they all had spark, and they all did. At this point, I also had a more experienced DSM'er come look, and he thought they looked ok. I put everything back, and it still ran like it did before (like crap). We also looked through the engine bay for obvious vacuum leaks, etc- but didn't find any.

Anyone have any ideas?

Thanks, Joshua

 

[talonz27]

check your iac and your tps sensors.

 

[jdhutchin]

I checked the TPS, it was fine. I need to borrow a tool from a friend so I can pull the ISC out and test it, which will probably be tomorrow evening. The ISC was replaced a little less than a year ago, so I'd think it should be fine- but I'll test it tomorrow anyways.

--Edit--
By "borrow", I mean get the tool returned to me after I loaned it out. Also, as a note, there is no CEL (and I never saw one while driving it)

 

[Locke]

Check that the timing belt didn't jump. Is it getting enough fuel?

 

[jdhutchin]

The compression test was fine, so I would assume the timiing belt didn't jump? (I did a quick visual inspection, and it seemed fine). How would I check and see if it's getting enough fuel?

 

[Locke]

The timing belt can jump a tooth and still give good compression. The only way to check is to look.

Install a fuel pressure gauge.

 

[talonz27]

yeah i would also see if its the fuel regulator

 

[15psi88]

might want to have a look at the caps in your ecu , with something as on/off like that.

 

[jdhutchin]

I checked the caps in the ECU, they were good. I then checked the timing on the cam sprockets... and they're off by two teeth, almost certainly causing the problem.

 

[Locke]

It'll run like butt with the cam timing being off, especially that far. Don't just re-time it, you will want to figure why the belt jumped in the first place. It is probably time to replace the idler, eccentric, and tensioner.

 

[jdhutchin]

Yep, that's the plan (replace timing belts, autotensioner, tensioner pulleys, etc)- I don't want to have to deal with this (or worse) for a while.

 

[Locke]

Nobody wants to. If you are not going to repair it right away, you should not drive it until after you get it fixed. If it were to jump many more teeth, your valves may collide with the pistons, and you will be having to do much more work, and spend much more money.

 

[jdhutchin]

Yeah, it'd definitely going to just sit until I get it fixed. I've already ordered all the parts, they should come in some time next week- looks like I'll be riding the bus until then.

 

[Locke]

Tip: Keep a small container of Vicks handy for when you board the transit bus.

 

[jdhutchin]

I replaced the timing belt, balance shaft belt, and all pulleys and the auto-tensioner. The car runs, but not very well. It still doesn't idle at all (I opened the BISS all the way). I can rev it, but it sounds just a little off, and when I let off the gas, it makes a noise that's almost like a pop- but I can still rev it again.

I'm about to go do another compression test- I'm guessing I may have been off a gear in the cam timing. Is there any way to check this without tearing everything apart again?

 

[jdhutchin]

Well, I tore it apart again, and found out that I was off by a tooth on the crank sproket.

 

[DSMDirkah]

If that does not fix the problem I would look at the ECU again. I had a 1g NT (1.8L) that would not run right when it was cold outside. If it was warm, it would run like a dream. I checked the caps and they looked good. Got another ECU at a junkyard and it never had a problem again. Just a suggestion