check engine light on 91 k1500 - Great Lakes 4x4. The largest offroad forum in the Midwest

Beyerle07 · September 21st, 2012, 10:14 PM

a couple years ago i did a 4.3 to 5.7 swap and it set off the check engine light. I put a 670 holly tbi on the truck and the second I put the pedal to the floor it throws a check engine light and codes are supposed to be a map sensor, knock sensor, or tps. Anyone have any experience in this??

wave_crusher · September 22nd, 2012, 01:35 AM

a couple years ago, just getting around to finding out the problem??

Does the light go off? It is off when you first start the truck?

My guess would be that it's the 02 sensors throwing a rich code with out any more info

Iggy · September 22nd, 2012, 11:13 AM

What are the code(s) associated with the check engine light?

Beyerle07 · September 22nd, 2012, 07:19 PM

No I'm just going to drive or on the road more and am sick of losing power. It's off when you start the truck and if you baby it it won't come on at all.

I'm not sure on the codes I just remember those were supposed I be the codes. I will check tomorrow when I start it up

wave_crusher · September 22nd, 2012, 10:47 PM

sounds like a tps, but does it idle funny or is the pedal response off??

Beyerle07 · September 23rd, 2012, 09:00 PM

No idles fine. Once the check engine light comes on it seems less responsive

davidkassie · September 25th, 2012, 11:32 AM

always tripple check those ground wires on the thermostat housing, and engine to frame, frame to body, etc. this injection system is very picky on grounds. good luck

Beyerle07 · September 27th, 2012, 10:30 PM

i checked the grounds and cleaned some rust off a couple, but still no luck i think i might try the o2 sensor

drogers · September 27th, 2012, 10:51 PM

that's obd 1 system all code will be gone as soon as you shut it off

they dont have a memory on that system .

wondering what trans is i and what all did you leave for the comp seance your running a carb?

Beyerle07 · September 28th, 2012, 02:47 PM

its all v8 computer and harness. it has 670 holly tbi system on it not a carb

montecarlo33 · September 28th, 2012, 03:40 PM

had the same thing on my 92 c1500 with a 4.3 in it. If i put it to the floor the check engine light would come on and I found I had a bad TPS.

drogers · September 28th, 2012, 05:52 PM

oh woops didn't see the tbi . sounds like a tps

Beyerle07 · September 29th, 2012, 06:17 AM

Well I'll start with that and let you guys know. Thanks

Beyerle07 · November 2nd, 2012, 10:44 PM

ok i found some wires that broke off and a couple of vacuum lines. i replaced and put them in the correct locations and also found the knock sensor connector was bad. I put replaced it and started up fine actually ran better pulled it out of the garage and put the diesel back in and it was stalling and acting worse then before. I am stuck now any ideas

it is pulling this codeDTC - 33 MAP sensor circuit error (signal high indicating low vacuum). I am planning on messing with the map sensor tomorrow and lines. But i'm not thinking this will help. so short of putting a carb on it
i'm stuck.

September 21st, 2012, 10:14 PM	#1
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	check engine light on 91 k1500 a couple years ago i did a 4.3 to 5.7 swap and it set off the check engine light. I put a 670 holly tbi on the truck and the second I put the pedal to the floor it throws a check engine light and codes are supposed to be a map sensor, knock sensor, or tps. Anyone have any experience in this??

September 22nd, 2012, 01:35 AM	#2
wave_crusher I'll Direc your TV Join Date: 01-20-09 Location: Big Rapids, MI Posts: 3,806 iTrader: (15)	a couple years ago, just getting around to finding out the problem?? Does the light go off? It is off when you first start the truck? My guess would be that it's the 02 sensors throwing a rich code with out any more info

September 22nd, 2012, 11:13 AM	#3
Iggy Member Join Date: 01-02-12 Location: Traverse City, MI Posts: 40 iTrader: (2)	What are the code(s) associated with the check engine light?

September 22nd, 2012, 07:19 PM	#4
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	No I'm just going to drive or on the road more and am sick of losing power. It's off when you start the truck and if you baby it it won't come on at all. I'm not sure on the codes I just remember those were supposed I be the codes. I will check tomorrow when I start it up

September 22nd, 2012, 10:47 PM	#5
wave_crusher I'll Direc your TV Join Date: 01-20-09 Location: Big Rapids, MI Posts: 3,806 iTrader: (15)	sounds like a tps, but does it idle funny or is the pedal response off??

September 23rd, 2012, 09:00 PM	#6
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	No idles fine. Once the check engine light comes on it seems less responsive

September 25th, 2012, 11:32 AM	#7
davidkassie Senior Member Join Date: 01-29-09 Location: BENTON HARBOR michigan Posts: 642 iTrader: (6)	always tripple check those ground wires on the thermostat housing, and engine to frame, frame to body, etc. this injection system is very picky on grounds. good luck

September 27th, 2012, 10:30 PM	#8
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	i checked the grounds and cleaned some rust off a couple, but still no luck i think i might try the o2 sensor

September 27th, 2012, 10:51 PM	#9
drogers Senior Member Join Date: 03-30-11 Location: owosso mi Posts: 211 iTrader: (0)	that's obd 1 system all code will be gone as soon as you shut it off they dont have a memory on that system . wondering what trans is i and what all did you leave for the comp seance your running a carb?

September 28th, 2012, 02:47 PM	#10
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	its all v8 computer and harness. it has 670 holly tbi system on it not a carb

September 28th, 2012, 03:40 PM	#11
montecarlo33 Fuckin A Join Date: 08-23-07 Location: Otsego County 49735 Posts: 2,213 iTrader: (12)	had the same thing on my 92 c1500 with a 4.3 in it. If i put it to the floor the check engine light would come on and I found I had a bad TPS.

September 28th, 2012, 05:52 PM	#12
drogers Senior Member Join Date: 03-30-11 Location: owosso mi Posts: 211 iTrader: (0)	oh woops didn't see the tbi . sounds like a tps

September 29th, 2012, 06:17 AM	#13
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	Well I'll start with that and let you guys know. Thanks

November 2nd, 2012, 10:44 PM	#14
Beyerle07 Senior Member Join Date: 06-04-12 Location: Freeland/mi Posts: 103 iTrader: (0)	ok i found some wires that broke off and a couple of vacuum lines. i replaced and put them in the correct locations and also found the knock sensor connector was bad. I put replaced it and started up fine actually ran better pulled it out of the garage and put the diesel back in and it was stalling and acting worse then before. I am stuck now any ideas it is pulling this codeDTC - 33 MAP sensor circuit error (signal high indicating low vacuum). I am planning on messing with the map sensor tomorrow and lines. But i'm not thinking this will help. so short of putting a carb on it i'm stuck.