BigFatBoss

This looks like I chasing a ghost. All I am doing is parts swapping it seems. Any of you people had this problem. I posted it about 2 months back but never seem to get it resolved. I did a tune up I even took the thing to a shop to have it diagnosed. They were wrong becuase I made the parts swap and it still did the same thing:

What it's doing:

- Hard starting in the morning. When it starts it runs smooth but when the pedal is depressed it immediatley wants to bog and die.

- Let it warm up and it's fine. Okay now to get on the road.

- While on the road it will behave fine then I will pull up to a stop or light (could happen at any time, no specific time this happens) and when I go after the light changes it show the same symptoms as when it was cold and hard starting. Starting it back up is a pain... but then it's smooth again.
- It will do the same thing again and again infrequently.

The shop said the ECU wasn't flashing any problem numbers. They diagnosed it as the Air Flow Meter. I swapped it with a working one... no change.

I am stumped and I would hate to take this thing to a dealer but it appears I have no choice. I need this car running as my wife is getting tired of carting me around.

Thanks for whatever help,
BigFatBoss

91zxtt

My guess would've been the MAF. I had a similar problem on my old Z31 and it turned out to be the MAF.

Maybe something with the cold start valve?

Unfortunately, the dealer may be your best bet. I'm just be guessing beyond that.

mdharris11

Ken,
I read your description of what it's doing -- get the Haynes manual and do the diagnostic first on the ECU. It may save you a lot of time trying to pinpoint the problem. CHTS could be the culprit. Sounds like something is intermittently failing or sending a fluctuating signal to the ECU. Run the diagnostic and report what it tells you, but make sure you do it exactly how it is described in the manual.

mnphysicist

I agree with the CHTS hypothesis, at least from the standpoint of bogging down when warm. As far as rough running when cold, and then everything being fine, its usually a stuck air regulator. Some units can be disassembled for cleaning, most are staked, and just have to be replaced. Cleaning a stuck unit with solvent is at best a very short term fix.

Ron

BigFatBoss

Will do. I am getting the manual this morning and will run the tests. I have been looking online for the CHTS. Can't seem to find one. Any idea where to get this part. When I look in the list for sensors it's not there.

Thanks

BigFatBoss

Thanks for the advice. The car never ran rough, it was only hard starting and bogging when gas is applied.

BigFatBoss

Okay,

Today I felt ambitious and thought I would tackle this thing. So I did a little replacing. I bought a new O2 sensor and I went to tackle replacing or at least inspecting the CHT Sensor. I got the fan off and the bracket that tensions the belt for the AC then I tried to get the timing cover off. Got it off most of theways and relaized that I would have to go deeper... drian the coolant so that I could get at the CHTS sensor. I live in a condo so I had to reassemble it and be happy with the O2 change. Made no difference so it seems. I went back out after I cleaned up to move the car back into the car port and the thing started right up... so I said lets take it for a ride... Ran great. Go figure. I know the problem isn't solved its just a matter of time berfore it raises its ugly head again. I will go back and change out the CHT Sensor and do a timing belt when I can get the car to a place I can get into it.

Bigfatboss

ZenArcher

If you want to change your CHTS you can find the part number here and a somewhat easier installation writeup here.