84 T-Type running questions

[MoeJr]

Just got the engine back into my 84 after a complete rebuild. The engine runs great with tons of power but has 2 things I need help on. 1: The idle isn't as steady as it should be and it has a slight tip in hesitation. 2: When just cruising the car feels like it is surging a bit. Does not surge when you're accelerating just at cruise. It runs strong so I am just getting ideas at what to look at. This is all 84 stuff no 86/87 conversions done. Also there is no black smoke coming from the pipes. The car is running a stock chip and a 160 degree TStat.

Any help is greatly appreciated, Moe

 

[fgordon]

Just got the engine back into my 84 after a complete rebuild. The engine runs great with tons of power but has 2 things I need help on. 1: The idle isn't as steady as it should be and it has a slight tip in hesitation. 2: When just cruising the car feels like it is surging a bit. Does not surge when you're accelerating just at cruise. It runs strong so I am just getting ideas at what to look at. This is all 84 stuff no 86/87 conversions done. Also there is no black smoke coming from the pipes. The car is running a stock chip and a 160 degree TStat.

Any help is greatly appreciated, Moe

If you've disconnected your ECM without disconnecting the battery that could be the problem. But first I would check the TPS adjustment. If the voltages are off it could cause the same type problems. I have experienced your symptoms twice once was a fried ECM and the second time it was the TPS adjustment.

Some of the really smart guys on here can probably offer some other possible solutions.

 

[Jerryl]

As stated.
Check your TPS and IAC. Start there.
If you have a scantool or access to one, it would be better as you can read the "vital signs".

 

[MoeJr]

Thanks guys. I had my Dad bring his scan tool home for me to hook up. It'll be the first time I hookl this machine up to an obd1 car. It is a Snap On Modis. Should be able to tell me everything I need. Will update you tomorrow afternoon.

 

[MoeJr]

Ok guys I got some readings at hot idle. The Block Learn was 126. The integrator was bouncing between 122 and 131. It was following the up and down of the 02 sensor. The TPS is set at .44. IAC was 78 at idle and rose as the throttle was opened. The MAF was reading 8 gm/cm. I could not set the min air rate. I disconnected the IAC and then started the car. Would not idle under 1100 even with the screw backed all the way out. Scan tool said this could be caused by TB coking which would also explain the high IAC numbers.
I do have a 160 T-stat in it. Car was reading 185 so thats good. Hope these numbers help. I did buy a new TPS today and also some BG 44K Injector and top engine cleaner. Won't get those in till Monday unless I get lucky. Keep the suggestions coming. Thanks.

Moe

 

[BRAD_PADGETT]

I would adjust the IAC to between 20-30 at idle in park. Your sign. tells everyone nothing. Garbage out- garbage in. Good luck- Brad

 

[MoeJr]

Brad you saying my signature is not telling people anything? I stated what mods the car had at the beginning.

Before I can get the IAC down to 20-30 I have to be able to set min air rate. I am gonna give the TB a good cleaning and install the new TPS and see if I can get it down. IAC is moving so that should not be the problem but if I have to I will buy one.

 

[MoeJr]

Update again. First new TPS was wrong one. Was the 86-87 one. Had to order 84-85 from Poston(part stores wanted 125-200 bucks Poston was 35). Got that all done and now TPS is at .44 and IAC at hot idle in park is 25. That got rid of the hesitation. The surging is still there but I am pretty sure it is because the Torque Converter is not locking at a low enough MPH. TV Cable adj. is all set. Seems if I get it up over 45 it locks up fine. Below that it is hit or miss. Sometimes it will lock and sometimes it hangs for a while before it decides whether it wants to lock or not.

Trans fluid looks and smells fine. Think maybe Lockup solenoid? Was there a chip revision in 84 for this issue? I think one of the years 84-87 had a chip revision for this. I am running the stock chip. Not sure whether it is the original or a replacement.

Thanks Moe