hey guys i did the 305 to 350tbi swap. changed what is supposed to be changed.. esc module, knock sensor, injectors.. well all of them were used. when my car warms up and i start to get on it the check enine light comes on and boy let me tell you... it's about as fgast as the stock 305.. and the 350 has got some work done to it. anyways i had autozone check the codes and the kid said code 43, and 54. i checked my haynes firebird manual and it said 43 was poor electrical connection, open or short in circuit; defective knock sensor; defective ecm. code 54 says fuel pump circuit defective fuel pump; defective fuel pump relay; defective oil pressure switch; poor electrical connection, open or short in circuit; defective ecm.

so i get a knock sensor and put it in.. would you believe i still got the check engine light.. so then i got the esc module, STILL get the check engine light.

so i scan it for codes again today and got the same 2 that the guys at autozone got.. 43 adn 54.

except i looked in a different code book for gm for obd1 and it says 43 is TPS out of adjustment. so my friend has a 305 tbi and he said when he put his motor back together he needed to replace the TPS because it was running terrbile and his cehck engine light was on.. but mine isn't always on.

what the hell can my problem be guys?

 

Let's let Shifty & company deal with this one.

 

Check all of your grounds.

 

well today my dad was also thinking about the TPS while he was off of work.. so i'm going to try the TPS thats on the 350 throttle body tomorrow and see if that works.. also when it first starts up it'll idle high and then drop and then high and drop and it'll do that until you start to run it for a couple of minutes. so he was also thinking of the tps and if thats not it i dunno!!1

 

Have you checked every electrical conector and ground. It sounds like you have a connection problem more than a hardware problem.

 

Hello Trans_am_ta_84,

For a TBI engine, code 43 = Electronic Spark Control (ESC) circuit and code 54 = Fuel Pump Circuit (Low Voltage). One other question, after you replaced all these parts. Did you disconnect the battery to clear the trouble codes before you drove it? This info is from the GM service manual and not haynes.

 

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page 4

 

hmm.

well i'll first say something that i know of.. i don't know what the problem is with the fuel pump relay.. because it doesn't take any longer to start then my friends 305 tbi.. and doesn't take any longer to start then it ever did before. i'm going to try a TPS and if that doesn't work i'm going to make sure all the wires are where their supposed to be..

trickster:

in the haynes firebird manual code 43 is exactly as you say.. but then there is another haynes odb1 code manual and it says 43 is a TPS. i don't have any idea why the heck code 54 would be coming up. i'll have to waite until tomorrow to see what the TPS is going to do for me.

thanks for all the help guys. i'll keep you updated.

also what type of wires should i look for that might be causing it? thanks

 

The reason for that is Haynes tries to cover a lot of model years in their books and they just give the bare basics on a lot of items. For the TBI engines, code 21 & 22 are for the throttle position sensor. 21 is signal voltage high and 22 is signal voltage low.

 

trans_am_ta_84,

These two threads should help with the code 43 problem:

https://www.thirdgen.org/techbb2/sho...ock+AND+forced
https://www.thirdgen.org/techbb2/sho...ock+AND+forced

RBob.

 

Hey Trickster what book is that???? I would love to have something like that for my car. I am having this same problem with knocking and I am now sure that it is my knock sensor that has gone bad.

 

It is the GM service manual, you can order one through Helm Inc. at the link listed below. At the top of the page is a list of manufacturers, click on General Motors and then pontiac or chevrolet and follow the instructions. The cost for yours would be $117.00 and right now it is listed as "Print To Order" There is also a convertible supplement that you can order for $3.00 and it also is out of stock. They are well worth the money.

http://www.helminc.com/helm/welcome_...MAV6HD8UAQDKS6

 

So, did you ever disconnect the battery yet, like Trickster asked?
Oh yeah, I just thought of something else to check.
I heard of a guy mixing up the Coolant Fan Switch plug with the Knock Sensor plug. Something else to check since they are so close to one another. (And no, it wasn't me!)

 

actually i put the chip in it and when i did the chip i disconnected the battery... but i am going to try that tomorrow while i'm at work. the TPS wasn't the problem either cause i tried that todya brian at tbichips said it i can't figure it out he will do something else with the chip that should cure the problem.

 

You said you put a chip in it? You might want to go back and make sure that chip is installed and seated properly. It can also give you headaches.

 

another thing i noticed on them other threads about this is alot of talk about the esc module. i'm sure i said this above but i tried a enw one of them and that didn't work, tried a new knock sensor, tried the TPS...

well i'm sending my chip back and he is going to do something with the esc with it.. and tomorrow i'm going to disconnect my battery for a few mintues to see if that will work. this is a real pain in the ***.

 

I have done bascially the same swap as you. My car is definetely got more @$$ to it now. Even if it is still a peg-leg. LOL
Did your motor come from a caprice or from a truck, like mine?
Just wondering, if you have the roller cam or not.
I have yet to change the PROM in mine, and it still seems to run pretty good.

 

my motor came from a truck (4 bolt mains) but i made it a roller cam.. cam, lifters, lifter retainer, cam plate. i used everything from my old motor other then cam and lifters. mine is also an open rear but i'm saving up to get a posi and i already have the 3.42's but no point in putting them in yet without a posi.

 

You have been changing out all these components, but have you looked at the wiring as a problem yet?

 

Cool TA84,
So I guess you had to tap the bosses that the cam plate (spider-looking thing) sits on?
Also, the lifter bosses were the same? I thought the roller bosses were taller to accomidate the roller lifters.
Mine is from an 87, a 2 bolt.

 

trickster:

i didn't yet but tomorrow me and my dad are going to try to work on it alittle bit. i'll mention the ground wire behind the head.. and i know the negative wire that goes to the battery is good because i did that.i disconnected the battery today to maybe see if it will work, i changed out the 350 injectors to the 305 just to make sure it wasn't the injectors (boy i think i know why i need 350 injectors now) i also played with the distributor alittle bit. i turned it clockwise and let me tell you it wouldn't even idle. then i turned it back cause i had to leave my job. so tomorrow me and my dad are going to put the 350 injectors back in.. play with the timing alittle bit.. look over the wiring.

i'm about to pay somebody to fix my car that has actually did a swap because it's starting to be a real pain and it seems like i'm not getting anywhere

 

2 years ago I had troble with code 43. The ECM tries to force a knock to see if the sensor is working. If the ECM cant get a Knock it assumes that the sensor is bad and goes in to limp mode where it backs the timing way off to be safe and gives code 43 SES light. You will lose alot of power in that mode. When you shut off the car it starts over normal till it fails the forced knock test again. I turned off the forced knock test in my chip and have not had the problem since.

 

JokerRS:

most likely i will be turning the forced knock off in my chip as well.

i put a new iac sensor on my car today. no more bad idle. i also had to change back to 350 injectors cause i put 305 injectors in it to see if my injectors were bad.so now it idles good..

now i have another problem. now the car won't start unless i give it some gas. you guys think maybe when i took the plate off to get the injectors something happened to that relay that brings gas to the motor? any idea?

 

I have a similar problem with extended cranking time before start up, but after the car is warmed up, it's usually fine. I have pointed in a lot of different directions on this issue. Starting from sparkplug gap, all the way down to the fuel pump.
The common theme that I have been getting is that the fuel is leaking past the regualtor, back to the tank when the car is off.
I am not too sure about that, but since I have just made a spare regulator into an adjustable one; when I change it and the gasket, I'll let you kow if there is any difference.

 

i'm thinknig it's the regulater too because before i touched it today it started up without a problem. even when mine is warmed up it does it. i think thats what the problem will be. i might jsut swap the 305 regulater with the one in the 350 tbi to see how that will do.

 

Well I replaced the whole upper injector pod onto the 305 TBI, (the 350 linkage was a little different), but since I did that, it has been not wanting to start right up. There was only one time that it fired right up. It had been sitting in my shop overnight and it shocked me! Other than that, I've tried turning the key on and waiting 10 seconds. That doesn't do it. I tried a quick crank and then turn back off, to see if it would pump up. That doesn't work either. I will tell you, that when I figure it out, I'll post and let everybody know what did the trick, for sure It's kind of embarassing having to sit there and let it crank for a while before it starts, ya know.
The only other thing I can think of, is that maybe the pumps for a 350 vs. 305 are stronger...

 

While you have the other regulator off, check this out.

https://www.thirdgen.org/newdesign/tech/tbi-afpr.shtml

Took me like 3 minutes to do.