KITT1983

iTrader: (3)

my car has a rough idle for some reason, when my car is under heavy load (such as going up a steep hill) or I just punch the gas pedal and then just let go of the pedal the car. the motor went to 300 RPM and bounced back I am at a stop light the cars idles real low at 500-600 rpm. In the morning when it is cold out it idles fine, when the motor is warm or it is warm out the motor goes to 400-600 rpm and the whole car shakes violently. I replaced both iacs the passenger side was dead and the drivers was half dead with carbon build up. the motor ran better but there is till a rough idle. would a 160 thermostat cause the rough idle, closed loop problems or spark plug fouling ? Is lucas good for fuel injector cleaning?

Jeff2012

Did you ever figure it out? Just bought one... from a light very sluggish. Just changed plugs, air filters, did synthetic oil change w lucas. Accel 8.8mm wires and cap and rotor... ideas?

KITT1983

iTrader: (3)

please define sluggish so i can help

KITT1983

iTrader: (3)

check the egr for blockages and vacuum leaks ?

how are all the vacuum lines? if any of the vacuum lines are dry and brittle or cracked. then you should replace them.

how are the IAC's working?

KITT1983

iTrader: (3)

it was a bad EGR, both IAC's were bad, there were several vacuum leaks at the back of both TBI's. The TPS was not set right at .525v, the idle was maladjusted and the 160 thermostat caused problems it was not running in closed loop

parts that caused the problem:

EGR
PCV valve
brake booster
vacuum selector switch
3 new IAC's one was defective
180 degree thermostat

Jeff2012

Not too sure I just bought it, kinda drags off the lines, rough idle, low end power isn't there. Injectors are spraying even. New exhaust. Took off AC system. It's just tough but I hear crossfires are the worst

KITT1983

iTrader: (3)

i would try injector cleaner such as Lucas or Techron chevron and check all the vacuum lines for cracks and leaks. also try some dry gas in case you filled up with bad gas.

next i would check the fuel pressure your fuel pump might be on its way out


what did you remove from the a/c system?

my car has no loss of power and i have a fully working a/c

Jeff2012

I took off everything AC related. Receiver dryer, compressor etc. The car sat for 6 years. I just put in shell 93 a couple days ago. Then changed the oil, plugs, air filters etc. Was thinking of doing a fuel injector cleaning.... maybe dump a lucas in the tank. I have a shop so thats relatively inexpensive. It runs good warmed up... or at least better... I put a double roller timing chain on it 6 years ago.. converted from belt driven fan to electric fan, did the oil pan gasket, timing cover gasket, valve covers, etc.... also it looks like theres a trans leak from the speed sensor behind the trans on the side... but was told it is the governor? hmmm

KITT1983

iTrader: (3)

What temperture thermostat do you have in it

chazman

iTrader: (4)

Where exactly were these vacuum leaks behind the TB's? I have a slight "stumble" a full throttle a lower RPMs. I admit, that I haven't changed out all of the vacuum hoses, but I've inspected them all and they look great.

I might want to consider a new t-stat too. I have no idea if mine is the original one. But the car runs pretty cool but maybe a little rich, (and I get pretty bad around town fuel economy). Looks like the radiator was replaced at some point too.

KITT1983

iTrader: (3)

What is the temperture that your car is running at?
What kind of radaitor do you have?
I would recomend either a 180 or 195(stock) degree thermostat
I made the mistake of running a 160degree thermostat and and it ran rich

All the lines and vacuum caps were dryotted from the inside my egr caused a vacuum leak

chazman

iTrader: (4)

I can't ever remember it getting passed 180 or so.

KITT1983

iTrader: (3)

Did you ever hit the second mark on the temp gauge in the cluster? I thought that the second mark meant 195 or 200 degrees?

KITT1983

iTrader: (3)

can you take a photo of of the temp gauge when fully warmed up and a video of who its running ?

chazman

iTrader: (4)

Next time I take it out, I'll pay more attention to it.

Tom 400 CFI

If it's been sitting for 6 years I would do a compression check. If it's low (rings stuck) run it and keep changing the oil...a lot. Use cheap oil for the multi changes...and it will come back. This is if a TEST shows low compression. Other important checks on a CFI are fuel pressure and vacuum leaks. Fuel pumps in CFI cars are marginal ("good enough") when working right...and often...they aren't working right, unfortunately. Get a gauge on there and check FP. Should remain consistent at ALL throttle settings. 9-13 PSI is the spec...generally they seem to "like" closer to 13 pounds. Stock timing is incredibly conservative. Advance it to "feed it what it wants".

If your injector show a "good, even spray pattern", I highly doubt they need attention. Focus on the points I mentioned above, and avoid the elixers.




Same goes to you. Check for vacuum leaks and Fuel pressure!! Vacuum leask can be any place they'd be on any F-body (vacuum lines, Evap canister, PCV valve, EGR, brake booster...but unique to CFI is the plenum lid. Bolts can and do come loose, and the lid gaskets are known to leak too.

T-Stat; I ran a 160 stat in mine for YEARS. Also ran with the cowl hood wired open, Thermac disabled and closed, and snorkle plugged (forcing CAI only). ALSO, I chopped out the coolant channel under the intake and welded that closed. With a fully ported intake and the "swirl plates" removed... the car only had issues (slight stumble on throttle tip in) when stone cold for the first 60 seconds or so. "Stone cold" was winter starts in Park City, UT. Cold.

I'm not advocating a 160 stat...but I AM saying that there should be nothing detrimental with using one, that is specific to CFI.

KITT1983

iTrader: (3)

i had a 160 thermostat in the car and it never ran in closed loop. i have a 180 thermostat in there now and the car seems to be running good around 185-200 degrees in 20- 50 degree New England weather and much better heat

Tom 400 CFI

Huh. Mine did. (?)

KITT1983

iTrader: (3)

when the 160 was in it. it rarely ran hotter than 156 degrees and normal operating temperature is around 220 degrees

Tom 400 CFI

That is interesting. The 160 T-stat shouldn't even START to open until...160. That means that the engine should run hotter than 160*...probably ~175ish, depending on cooling system, engine configuration, etc.

Still, my '83 would go into closed loop at around 148*F.

Either way, and my point about the T-stat, is that a 160* t-stat should not be the cause of running rich. Does your car (now) run rich as it passes through 156* on it's way to operating temp? If it does, there is something else that is causing that, and why you observed the issue that you did.

KITT1983

iTrader: (3)

No it now runs normal and now runs in closed loop. I now get better gas milage and heat from the heater

chazman

iTrader: (4)

You know, I was thinking about both the lid gaskets and the TB/air cleaner gaskets. The top lid bolts were pretty loose when I got the car, tightening them made a world of difference. Every now and then, I need to go back and retighten them again though. .

Tom 400 CFI

You can spray around the lid w/a combustible like brake cleaner, WD-40 or even propane to test for a lid leak. I'd BET, that after several tightenings, the gasket is squashed around some of the bolt holes. Certainly worth checking, IMO

Air cleaner > TBI unit gaskets doesn't constitute a vacuum leak. No vacuum there (one would hope). At worst, a bad gasket there might let in a smidgon of dust over a long period of time. But those gaskets don't do much. Probably as much to prevent vibrations/wear of the steel on aluminum, as to seal anything.

chazman

iTrader: (4)

While we're talking about stuff, my intake base plate must be loaded with carbon. I've previously done the Seafoam things afew times. I do put Seafoam in all the Camaros during winter as a fuel stabilizer. When ever I have Seafoam in the tank of my Crossfire, this what comes out.








That's carbon. If I start it up and rev it, it'll do that every time until I've used up the tank of Seafoamed gas.

KITT1983

iTrader: (3)

i see from time to time in the winter from my KARR's exhaust

Tom 400 CFI

Yeah... mine did that too, and I never touched "Seafoam"...and never will. Stay away from the elixirs. Did you know gasoline already has detergent in it, and that alone, will keep the inside of your intake clean?

MREtransam

PLEASE HELP

Hi, I have a 1983 Pontiac Trans Am, 5L V8 CFI, Its a Mecham Racing edition number 59 of 150, because of this I want to keep it original. I am having a few issues at present... I am new to all this so please bare with me.

I'm getting fault code 21... so I checked the TPS. Blue wire is reading 4.2+ Volts and Doesn't change when you adjust the TPS at all. Also I can't get an earth on the black wire. And I don't think the grey and blue wires are connecting, as I am not get any volts going through when plug is disconnected... Does this mean I will need a new TPS?

Car idles pretty terribly.

The car seams to be using far to much gas.. about 12MPG

it also splutters and runs badly at low throttle settings... seams to be better at high throttle settings. (lacks the power I think it should have)

I am in New Zealand, so dont have access to spare parts very easily or quickly.. My car is all original as it was bought new in the US in 1983.

ex-x-fire

You need to do a continuity test between the tps connector & the ecm connector, you'll need a ohm meter & a good service manual.

Tom 400 CFI

What ^he^ said.

KITT1983

iTrader: (3)

here is a link to a GM service manual

http://www.ebay.com/itm/1983-PONTIAC...item4151b7943f

MREtransam

Thank you for that... so just to clarify, i need to set it via ohms resistance between the blue wire and the grey wire? and what does it need to be set to? thanks

KITT1983

iTrader: (3)

Bump

KITT1983

iTrader: (3)

Bump

KITT1983

iTrader: (3)

Bump