Crumpler

Hey Mike, thanks for pointing me in the right direction.
That makes more sense, I also went into Dwayne's write up last night to get more education.

So TPS is on, and I get nice, spec. readings on the sensor, harness, and LH.

I will start assembling later today and then see how much this had to do with the original problem.
No overt issues found on hoses, etc. while I was in there.
Regards.

byrdman454

How old is you MAF? Has it been rebuilt before? This could be another reason for the running issues.

If the car is bucking wildly, I would guess it is running lean. This is how my Dad's '84 Euro reacted to a lean condition.

byrdman454

Has Daddio's MAF ever been rebuilt? If so, you could do a quick swap and see if it helps things.

We might have to throw my smoke machine on there and check for massive vacuum leaks...

Crumpler

Hey Mike!
Good news in that my MAF is fresh rebuild two months ago.

Bad is that, she is in fact lean. So vacuum leak may be underlying issue.
With MAF ohms down to stock 380, I get AFR on wideband that are ugly (ie 16-17 at 3000).

Oooooh. Smoke machine!

PorKen

Is that AFR measured with the O2 sensor unplugged?

davek9

Hi Ken, I was wondering and going to ask, where do you recommend disconnecting the O2, and all three wires or just the main single?

I was thinking that only the Main feed (coax) and leave the two heater wires connected and do this at where it comes through the floor by the CE?

Thanks,

Dave

Crumpler

Hey Ken, thanks for looking out for a rookie, last AFR's were with O2 sensor hooked up.

Based on your post I was going to get next readings with the O2 unplugged and go from there. I should, hopefully, be able to get her put back together tonight and see what's up.

Crumpler

Ok...

Assembled.
Connections rechecked.
18 cm Hg vacuum at EZF

AFR off innovate wideband on x pipe:

AFR with O2 sensor is 16.5-17.1 at idle, 800 RPM
AFR with O2 sensor unplugged (all three wires) is 13.5-14.2 at idle, 1100 rpm.

MAF at 380 stock.

SMTCapeCod

Higher idle is another indicator of vacuum leak.
Unless resetting the maf is implicated in idle adjustment.
But I've seen 17 referred to as a solid reading so you seem to be in good shape there.
Did you check the vacuum line manifold under the air cleaner, where several lines come together? Seems like you would've picked up most other candidates in the course of your work to get the TPS.

PorKen

Very good, grasshoppa. 18" is decent. Rebuilt MAFs will tend to be on the rich side. Hopefully you just have to adjust the MAF CO screw and the Throttle Body screw.

Plug the O2 sensor back in and jumper B to C on the diagnostic plug at the front of the engine. Engine must be warm but not too hot. A/C off.

Adjust the TB screw (7mm socket at the front of the TB), CCW for a 680-700 idle. (Use an external RPM meter not the dash tach.)
Adjust the MAF CO screw CCW for high 14 AFR (probably will be around 370).
You may have to repeat the steps above a few times. They affect each other.

Disconnect the B->C jumper. Rev up the engine to 1500 for a few seconds.
Replace the jumper and recheck AFR and RPM.


Note the TB screw always has to be open at least one full turn. Never completely closed.
The IAC/ICV design requires it to be open a little or it may occasionally stall.
If the idle cannot be lowered below 700, then there is a vacuum leak, or the TPS idle switch is not closing.

Crumpler

Appreciate the help Ken, I'm looking forward to getting her Porkenized!

I will get on it and post again.

I'm also going to go back and check every hard and soft vacuum line and connection.

Regards.

The Fixer

Hey Dave,

I sometimes use propane in the suspect areas to detect a vacuum leak (motor idling), you'd note a raise in idle.
You've probably done this too.

Hope you get this figured out soon.

Matt

byrdman454

Dave, I have a timing light that has a RPM indicator built in if you need one.

Crumpler

Thanks Mike, I was able to borrow a external RPM sensor off of Chris (thanks Dadddio).
I'm curious to see how close my stock tach is too the actual RPM.


It's a nice unit. Sturdy with comforting 1986 tech!

Attachment 863944


Matt, I have heard of that trick, but never done it.
I need to get in there and check every single vacuum line and connection today. Sure would be nice to find something easy.
So if it's a closed system, would I still be able to get 18 at EZF if there is a massive leak?

Mike I will keep you posted, there's a chance I will need your brain (and smoke machine) before this is over. Maybe we can bump that St. Louis tech session up if I can't fight my way out of this paper bag.

Cheers.

The Fixer

Dave,

You probably do not have a massive vac leak all of a sudden.

Your car ran very well prior to installing the new chips. That we know.

You either damaged something when installing Ken's product (doubt that you're a Vet) or Ken's product was damaged in shipment
because he tests prior to.

I'd put everything back to stock to see if your car will run right again.

If not you will know you damaged the board or Ken's product was damaged somehow.

If it does run fine once again, it's Ken's product.

Stuff happens sometimes during shipping.