Knock sensor questions
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Knock sensor questions
I've recently put a 355 with a HSR in place of my all stock LB9. I transferred all my sensors over to my new motor. I'm having a ton of timing being retarded and a code 43 being set.
Question 1. If you put a 305 knock sensor in a 350, will it cause the timing retard?
Question 2. Which plug is for the knock sensor and which is for the fans? I can't find any pictures and frankly, it's been a while since I pulled a motor in one of these and I forget which is which.
Question 1. If you put a 305 knock sensor in a 350, will it cause the timing retard?
Question 2. Which plug is for the knock sensor and which is for the fans? I can't find any pictures and frankly, it's been a while since I pulled a motor in one of these and I forget which is which.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: Knock sensor questions
your problem is the knock sensor is different from 305 to 350... get a knock sensor for that year 350 and your problems will go away.... also if you just swapped everything over that mean your injectors are at 19 pounds with that 355 hsr which would also cause problems... 350 tpi cars came with 22 pounds stock and you need a computer tune so the computer know its running 19 pounds or else you would lean out...
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
I've have the Moates Ostrich 2.0 emulator and 42lb Bosch "Green Giants" ready to drop in as soon as we get it to the dyno. We're trying to get Steve Kan back up here to Iowa to tune a few cars and I'm trying to shoot for that, probably around June 25th. Currently, I've got a set of LT1 24lb injectors in it, but the ECM is still running the stock 305 PROM. Just trying to work out the bugs, and the timing thing is kinda throwing me off.
So, the darker connector with the white wire is the knock? I'll probably just do the ground test and see which one turns on the fans anyway just to make sure.
So, the darker connector with the white wire is the knock? I'll probably just do the ground test and see which one turns on the fans anyway just to make sure.
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
Got under the car today. Did the ground test and I had them switched of coarse. Got the right connector on the right sensor and it's still doing the same thing. I ohmed the sensors. I got 39XX on the sensor that was in it. I went to the parts store and bought a brand new sensor for a 350 and it measured out at 38XX. You think I already have a 350 knock sensor in it and it's just the lack of changing the PROM to a 350 that's causing it?
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From: CT
Car: 1986 Camaro SC
Engine: 305 TPI Procharged D1SC
Transmission: Tremec TKO-600
Axle/Gears: Moser 12 Bolt 3.73 posi
Re: Knock sensor questions
man i'm a bit rusty, 89 was still a maf car right? 90-92 is speed density, i know on the speed density the esc was on the prom, you need a 350 knock sensor, do not over tighten it! you will destroy it, trust me, i replaced a knock sensor and nothing but problems i changed it out again and it was fine.
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
I swapped in the new KS for a 350 and it didn't change anything different. I'm thinking the PROM HAS to be replaced.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: Knock sensor questions
you need a 350 prom and computer.... here is the info from tpi parts.com....
ECM
Although there were several different ECMs used depending on what year TPI setup you have, the same ECM was used for 305 and 350 engines for a given year. The difference between the engines was the prom. In other words, the 86-89 350 TPI engines used the 1227165 ECM, and so did the 86-89 305 TPI engines. The 90-92 350 TPI F-Body engines (Camaro and Firebird) used the 1227730 ECM, and so did the 90-92 305 TPI engines. The 1985 305 TPI engines used 1226870 ECM, which is the same as the 1985 350 TPI ECM (350 was only available on the Corvette in 1985).
The Corvette used the 1227727 ECM on the 90-91 350 TPI engines. Although the Corvette was never available with a 305, the 1227727 ECM can be used on a 305 if desired.
PROM
This is probably the most important change that needs to be made. Regardless of what ECM you are using, the 305 prom is setup very differently from a 350 prom. Which prom you need will depend on what ECM you use, transmission type, engine size, and a few other details. Contact us if you need help finding the correct PROM for your application.
If you have a 90-92 ECM, and you are having your PROM reprogrammed, you must start with a PROM that was originally for a 350. The 90-92 PROMs have the ESC circuitry onboard, and that cannot be changed.
The 85-89 PROMs can be changed from one engine size to another without worrying about ESC within the PROM, since the module is external on those years.
Although there were several different ECMs used depending on what year TPI setup you have, the same ECM was used for 305 and 350 engines for a given year. The difference between the engines was the prom. In other words, the 86-89 350 TPI engines used the 1227165 ECM, and so did the 86-89 305 TPI engines. The 90-92 350 TPI F-Body engines (Camaro and Firebird) used the 1227730 ECM, and so did the 90-92 305 TPI engines. The 1985 305 TPI engines used 1226870 ECM, which is the same as the 1985 350 TPI ECM (350 was only available on the Corvette in 1985).
The Corvette used the 1227727 ECM on the 90-91 350 TPI engines. Although the Corvette was never available with a 305, the 1227727 ECM can be used on a 305 if desired.
PROM
This is probably the most important change that needs to be made. Regardless of what ECM you are using, the 305 prom is setup very differently from a 350 prom. Which prom you need will depend on what ECM you use, transmission type, engine size, and a few other details. Contact us if you need help finding the correct PROM for your application.
If you have a 90-92 ECM, and you are having your PROM reprogrammed, you must start with a PROM that was originally for a 350. The 90-92 PROMs have the ESC circuitry onboard, and that cannot be changed.
The 85-89 PROMs can be changed from one engine size to another without worrying about ESC within the PROM, since the module is external on those years.
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
Seems to make sense. It's just finding a PROM is becoming next to impossible. I've called every junk yard I can find. Checked Craigslist. This forum. Nothing. I even drove for an hour and a half yesterday to a guy's house that was parting out a few F body's. He said one was 350 TPI. I double checked with him on the phone and he was for certain it was a 350 car. I drove down, ask him what motor was in the car. "It's a TPI". I said "a 305 or 350". He goes "oh, it's a 305. shouldn't matter" Handed him the ECM back and got back in my car. I was pissed to say the least.
The whole thing is just weird to me. I had a 350 car before that I put a 383 in and ran all the stock stuff without any issues. Just weird that the 305 to 350 conversion is so drastically different.
The whole thing is just weird to me. I had a 350 car before that I put a 383 in and ran all the stock stuff without any issues. Just weird that the 305 to 350 conversion is so drastically different.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: Knock sensor questions
what year is your car and what computer are you running now..
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
It's a 91 Trans Am, Manual Trans, HSR, running a 7730 ECM. I'm planning on having it tuned, which makes me ask, if I'm going to tune it anyway and change it essentially, would my 305 PROM work to do this?
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From: Peoria, AZ
Car: 91 Z28, 2000 T/A
Engine: SBC 355, LS1
Transmission: T56, T56
Axle/Gears: 10bolt 3.73, 3.42
Re: Knock sensor questions
According to PCMforless you can use any V8 prom as long as it's correct for the ECM. The "limp home" portion of the Prom is the same 305 vs 350 and that is all you are using since the adapter board bypasses the stock prom's programming.
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
That's what I thought also. So basically, put in a 350 knock sensor and take it to get tuned?
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
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Re: Knock sensor questions
why would you wanna run 42lb inj? 24's are supposed to good up toward 385 hp or so.
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From: Peoria, AZ
Car: 91 Z28, 2000 T/A
Engine: SBC 355, LS1
Transmission: T56, T56
Axle/Gears: 10bolt 3.73, 3.42
Re: Knock sensor questions
I'd ask the tuner about the Knock sensor, I know they usually get desensitized on heads/cam cars because they detect false knock, it's worse with the bigger and more lope your cam has. They can tune for the injector size so go with you 42's since you already have them and your ready for future upgrade growth room.
Last edited by 3rd gen Will; May 27, 2011 at 05:32 PM.
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From: Peoria, AZ
Car: 91 Z28, 2000 T/A
Engine: SBC 355, LS1
Transmission: T56, T56
Axle/Gears: 10bolt 3.73, 3.42
Re: Knock sensor questions
Not true on the prom, if you are getting a tune. you can use any V8 prom as long as it's year correct for the ECM.
Second page
http://www.pcmforless.com/install/Ch...01986-1993.pdf
"example: 91 camaro 5.7 V8 must have a stock prom from a 91 V8, Different displacement OK. A V6 prom will not work in this application."
Second page
http://www.pcmforless.com/install/Ch...01986-1993.pdf
"example: 91 camaro 5.7 V8 must have a stock prom from a 91 V8, Different displacement OK. A V6 prom will not work in this application."
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From: Delaware
Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: Knock sensor questions
Not true on the prom, if you are getting a tune. you can use any V8 prom as long as it's year correct for the ECM.
Second page
http://www.pcmforless.com/install/Ch...01986-1993.pdf
"example: 91 camaro 5.7 V8 must have a stock prom from a 91 V8, Different displacement OK. A V6 prom will not work in this application."
Second page
http://www.pcmforless.com/install/Ch...01986-1993.pdf
"example: 91 camaro 5.7 V8 must have a stock prom from a 91 V8, Different displacement OK. A V6 prom will not work in this application."
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: Knock sensor questions
I am actually making 20 more hp with the new "stock" style chip vs my old hypertech chip.
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
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Re: Knock sensor questions
Have a look. I made more power with the v6 chip reburned with an AUJP bin. Car is a bolt-on 350 tpi.
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From: Peoria, AZ
Car: 91 Z28, 2000 T/A
Engine: SBC 355, LS1
Transmission: T56, T56
Axle/Gears: 10bolt 3.73, 3.42
Re: Knock sensor questions
I am assuming you took the stock prom out and soldered in an adapter to put a burnable prom in it?
I am just going off what PCMforless says, I don't know much about the V6 chips, I can see how the "limp home" portion would be different for a 6cyl vs and 8 cyl. Maybe not, I don't know.
Is that 305/400 RWHP/TQ? Is that is stock heads/cam with no power adders?
Custom tune > Hypertech any day of the week!
Last edited by 3rd gen Will; May 27, 2011 at 05:56 PM.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: Knock sensor questions
you can run a 350 tpi on a 305 computer but it will run like crap..... you can either take it somewhere to get it completely retuned... or buy a 350 computer of the same year and tune it accordingly to your mods.... if i were you i would get a 91-92 350 tpi computer because starting in 90 the esc is built into the computer... 85-89 have an external esc and its a yellow box usually behind the so called glove pouch that we have in our cars.. and have someone burn a chip for you using that 91-92 350 tpi computer.....
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
I had a guy call me today and tell me this exact same thing. Said one from a 4.3 Blazer would work so long as it was reflashed, which tells me my PROM will work as long as I'm getting it reflashed.
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Thread Starter
Member
iTrader: (1)
Joined: Jul 2008
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
you can run a 350 tpi on a 305 computer but it will run like crap..... you can either take it somewhere to get it completely retuned... or buy a 350 computer of the same year and tune it accordingly to your mods.... if i were you i would get a 91-92 350 tpi computer because starting in 90 the esc is built into the computer... 85-89 have an external esc and its a yellow box usually behind the so called glove pouch that we have in our cars.. and have someone burn a chip for you using that 91-92 350 tpi computer.....
Joined: Jul 1999
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From: CT
Car: 1986 Camaro SC
Engine: 305 TPI Procharged D1SC
Transmission: Tremec TKO-600
Axle/Gears: Moser 12 Bolt 3.73 posi
Re: Knock sensor questions
i have not tuned in a while, when i did my 305 TPI swap from carb, i was under the impression you need a 305 memcal for a 305 and a 350 memcal for a 350... the ESC is built on the memcal.
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
I understand the best deal would be to find a PROM for a 350, but that's a little bit easier said than done. Nobody has one. Nobody sells them. I found 1 used one for $428 on a GM site. I'm sorry, but that's a little out of my price range for something that I'm going to change anyway with tuning. So can anyone give me a definite answer? Will my 305 hardware be sufficient enough to use to tune with?
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From: Delaware
Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: Knock sensor questions
Now you are contradicting yourself. You just said he needs a 350 chip, but now you are saying you used a modified V6 one for your V8.
I am assuming you took the stock prom out and soldered in an adapter to put a burnable prom in it?
I am just going off what PCMforless says, I don't know much about the V6 chips, I can see how the "limp home" portion would be different for a 6cyl vs and 8 cyl. Maybe not, I don't know.
Is that 305/400 RWHP/TQ? Is that is stock heads/cam with no power adders?
Custom tune > Hypertech any day of the week!
I am assuming you took the stock prom out and soldered in an adapter to put a burnable prom in it?
I am just going off what PCMforless says, I don't know much about the V6 chips, I can see how the "limp home" portion would be different for a 6cyl vs and 8 cyl. Maybe not, I don't know.
Is that 305/400 RWHP/TQ? Is that is stock heads/cam with no power adders?
Custom tune > Hypertech any day of the week!
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From: Des Moines, Ia
Car: 91 Firechicken
Engine: 355ci SBC
Transmission: 97GM BW T-56
Axle/Gears: 9", Moser 31 Splines 3.73s Trac Loc
Re: Knock sensor questions
I took the car to Dynosport in Lincoln, NE. Great guy. He basically burned a programmable chip that I in turn used with my Moates adapter. So yes, You can use a 305 prom as long as you have a tune burned onto the chip for a 350.
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