The Sunbirds Almighty Confusing Electrical System

Evilcowboy420

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Well I have apparently learned a lot about the ECM and electrical system in this car since owning it. I figured I would share in the event someone else has any problems with their car. Most drive ability problems and issues with these cars can almost always be traced to an electrical component failure. So here are a few quirky things and the problem they cause.

1. Stalling/Surging Idle (Hot) - Replace IAC Valve, also could be a TPS.

2. Thumping/Bucking on slow acceleration uphill - Replace ICM, Rotor, or Ignition Coil.

3. Stalling/Hard start (Cold) - Replace IAT Sensor


These are just a few of the issues these cars can have if a sensor or electrical part fails. The ECM in these cars are actually pretty smart and will let you know when a failure happens by acting quirky.

Below is what code will be thrown when some of the electrical components fail.

TPS - Code 22 will always be thrown. This is either the fuel cut off relay or the TPS. Most likely the TPS.

IAT - When failure occurs no code will be thrown. The only indicator it isn't working is hard starting car. The reason no code is thrown is it when it fails usually it will read as a -40 c. This tells the computer it's working but its just really cold. The car will dump gas to the intake to compensate and flood the engine.

IAC - Another No code. When these fail they still kind of work. This has been observed on my own car with 4 different ones. 3 used factory ones and finally a brand new replacement. The pintle moves in and out as it should but will be unable to dial in a setting. I was told by GM themselves they were junk back then and commonly failed. My guess is the pintle gets stuck mostly out and can't return to a 0. When this happens most people would try to compensate by adjusting the base idle screw. This will work but will cause the car to be in clear flood mode due to the non adjustable TPS reading much higher causing a very lean running car.

ICM - No Code either quits or timing will act out of sorts. ie. thumping under load or bucking.

CTS - This should throw a code either 14 or 15. Best to replace anytime you replace a thermostat.

O2 sensor - 44 or 45 is what it commonly throws. Not much noticeably changes but if it is original then its bad by now.

This is by no way a complete list of electrical issues with this car but it is a list of what I have seen most commonly complained of when it starts acting funny. ie. intermittent drive ability issues.

These cars were reliable cars in their day but are also one of the most neglected cars due to the low cost and cheap parts it is made from. The engine is notorious for oil leaks. Especially the seal between the tranny and engine, the gasket between those as well, Crank seal, cam seal, ATF pan, Oil pan (thin metal and will almost certainly warp trying to remove it), drain plug gasket, head gasket, cam carrier gasket, freeze plugs and water outlet gasket.

I will say once all unnecessary parts are removed from the engine to make more room it is quite a fun engine to work on.

Anyway good luck to anyone trying to figure drive ability issues on these cars. But of them all that will stump most is the surging and rough idle. Save a ton of head ache and just replace the IAC with a new one. It will save you quite a large hunt.
 
thanks for the post
 
NP guys. Thanks for reading.

I just had fun replacing a ball joint today cause one of my new ones failed on me. Nice pop an clunk from the front. I am also getting a new oil pan. Im gonna paint it red before it goes on I figured it will be easier to see a leak streaming down over a red surface vs a black one. So she is still costing me money but she is getting fixed slowly but surely.

I also got a welder for Christmas to do some body panels and clean up some worn out rocker panels. Should be fun lol.
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I just had fun replacing a ball joint today cause one of my new ones failed on me. Nice pop an clunk from the front. lol.

What brand? ( let me guess --- Durafail?) TRW was the best ( no longer in business) with Moog a close second. I dont know any other good brands............

Lincoln welder?

Doug in P.R.:cool:
 
What brand? ( let me guess --- Durafail?) TRW was the best ( no longer in business) with Moog a close second. I dont know any other good brands............

Lincoln welder?

Doug in P.R.:cool:

Na the replacement was durafail lol the one I put on there to begin with was Valuecrap. Autozone is like the only place around here..... Well that and Advanced auto. Both sell about the same quality parts.

The surprise was the duralast one was made much better than the valuecrap one. From what I get from their company is always buy the expensive one cause the the quality is better than their second rate crap.

When summer rolls around I will probably just order Moog joints and linkage and replace them. I found some nice new lower control arms with ball joint already in on ebay for like 43 bucks so I may go that route since just to make everything look good.

Na I'm poor so I had to grab a Harbor Freight welder. I'm more comfortable with a mig so I opted for one of those. But I ain't gonna lie it works very well and can even get through 1/4 inch mild steel which is good enough. The duty cycle is only 2 minutes with 10 minutes rest. So it's a bit on the low side in that department. Good earth cable but no polarity reversal knobs so it is solely just a flux core welder and not meant for anything but flux core wire. Also no gas input. But I am only doing body work with it so I think it will be just fine for that. It honestly is a fun little machine and highly recommend it for its functionality and quality. It really surprised the hell out of me. No a lincoln or Miller but is good for a lower budget.

This bird still has a little ways to go to be what it once was but not too far. Gotta do tranny to engine block gasket and main seal (will do in summer time) and I am doing the oil pan this Sunday and finally I think the heater core blew out on me (slow heat, antifreeze smell in cab slightly and coolant disappearing very slowly) But I could get lucky and it only be a minor leak at one of the hoses. After that is done. It will be time finally to work on fun stuff like a 3 inch straight pipe with a glass packed muffler just to make it sound better. But I do think the red oil pan is gonna look sweet.
 
Cant beat the HF welding wire 10 lb spool I have in my Lincoln welder , I guess its made in Italy like my first welder, a HF arc welder.

It lasted 20 years before I burned it out, the jack I have from HF is past 20 years also, seal leaked twice..... fixed it with a correct metric seal , second time with a green a/c oring . :D

I'ved used the 10 lb HF wire over a year now and its still not even half gone yet. Sure beats the 2 lb rolls...;) The Lincoln HD 100 I have is about 5 years old and has given me no problems yet. ( even dropped it a few times )

I dont use gas either , didnt want the hassle of lugging around the tank even after I bought the HF cart. Right now the cart cant even get out of the house cause I have no workshop and the house foundation is too high off the ground too.

The only thing that I had go bad from AZone was the Duralast Timing chain set for the 2.2 in my old 2000 S10 , bought the Cloyes set the next time around.

Good luck working the brutal cold this weekend , my sister just sent pics as I'm typing this.:D

Doug in P.R.:cool:
 
lol yeah I may put off the oil pan until it warms up a little more. The leak it has isn't too bad. I just have to keep an eye on the oil. My in-laws garage isn't heated so you can only guess how long the RTV will take to set up. lol I can't stand shitty NY weather. lol

I saw a guy on youtube claiming that AT-205 in his jack stopped the leak for a long time. May save ya a little time if it ever starts leaking again.

Yeah I will probably go tomorrow and pic up a decent size roll from HF tomorrow. I like having as much supplies as I can have. Passengers side rocker panel is getting hit hard I just hope it holds out until there is no snow so I can start putting on some panels before I don't have anything to weld it to. lol

I miss my S10 I use to have. Aside from the spider injectors and the weird thing common with the ABS on those trucks, it was my favorite truck. I just wished GM would have did better body work. Those cab corners go before the frame even gets any surface rust lol. Oh and they need to get rid of that chevy lean they all pretty much had. lol I chased that for a while until someone finally said they all lean a little on the drivers side lol.

But I am saving for an impala now. Still unsure if I want a 62, 65, or 73. Gonna try and make it a beast.
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But I am saving for an impala now. Still unsure if I want a 62, 65, or 73. Gonna try and make it a beast.

My first 3 cars were 62 Full Size Chevys ( 62 Bel Air Sedan 283/PG - 62 Impala Wagon 283/PG - 62 Impala SS parts car)

Today, I'm more in favor of '69 Full Size Cars , probally a 396 powered one and swap in a 4 speed. Id like to find a a 2 door Bel Air, but an Impala or Caprice would do also.

The '69 427 cars are out of reach moneywise , friend back in the 80's in Rochester had a stock 73 454 Caprice, I guess his uncle won a lot of street races against the coworkers at Kodak after work.

Doug in P.R.:cool:
 
I love your posts EC. Verbosity!
Never overlook leaky spark plug wires as a cause for F'd up B/S!
 
I love your posts EC. Verbosity!
Never overlook leaky spark plug wires as a cause for F'd up B/S!

lol being thorough is never a bad thing lol.

I use to try to explain things in simpler terms to people but after one too many huh's I just went with explaining about everything I can.

A lot of people where I live tend to be a bit hard headed.
 
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