MAP sensor?

[HotRodPC]

My '88 700R4 will lock up in 3rd and 4th, as far as I know, that's how it's supposed to be.

I've seen them both ways and be correct. But I didn't realize it went as late as 88. Out of curiosity, so how does it get to OD from 3rd Locked Up? Does it unlock, then go to OD, then LU again, or does it stay locked up and just go to OD.

 

[oneluckypops]

I've seen them both ways and be correct. But I didn't realize it went as late as 88. Out of curiosity, so how does it get to OD from 3rd Locked Up? Does it unlock, then go to OD, then LU again, or does it stay locked up and just go to OD.

This all depends on which conver is in the trans.


If the Trans is truly from a 92 then I would say it is pcm commaneded lock up. and not the vacuume

 

[oneluckypops]

And his may be delayed even longer since his speedo is lying and not accurate.

This is my first thought. But its late and my brain hurts, damn why cant they ALL be E models? They are SOOOOO much easier to diagnose.

 

[oneluckypops]

Ok **** it 1 more before I go to bed.
Vacuum operated TCC was in the 700R4
Electronic controled TCC is in the 4L60
no TV is in the 4L60E 93+

I am trying to remember when they changed the 700 to the 4L60? What ever year the switched to 4L60 is when they changed to the electronic controlled Converter and not vacuum.

I still say till the TV is adjusted properly were pissing in the wind. What concerns me with this is he installed a spacer plate.

 

[CknightK10]

Ok so here is what I know. The reason that the truck has a 1992 TBI swap and not a 1994, is because (Doug, the previous owner) Didn't want to switch out the tranny. Probably due to more electronic issues. To my knowledge the 700r was used up until 1992, so that is why he purchased the 92 TBI create motor which would use the same TC. Up until about a year ago, the tranny had not been touched other than a shift kit, and had about 300k miles on it, being the only part of the drive-train that had not been rebuilt. Obviously with that many miles it was bound to go out and it did about a year ago. The truck sat around for a few months, then I took it to a local tranny shop and they rebuilt it, and put a shift kit in. Ever since I got it back about 8 months ago it has been having this issue and I had not done any research on the TV cable.... All I knew is, that if hooked up wrong, it would burn up my clutches very fast, so I never ****** with it. I always thought this was how the "new" tranny drove and never really worried about it until one day I threw a diagnostic code which turned out to be the knock sensor.

After driving the truck tonight when I adjusted my TV cable according to that amazing link HRPC gave me, The truck drives completely better.. 1-2 at 20mph 2-3 at 30mph and 3-4 right at 40mph. It even down-shifts perfect now with no issues yet!!!! So I do not believe there is anything wrong with the tranny what-so-ever. Just the TV cable was adjusted improperly in the first place which I had already suspected, but just trusted the mechanic at the tranny shop knew what he was doing.... Guess that was a failure.

Whats concerning me now, is the fact that the CEL pops on when ever I get on the throttle at all and the truck goes into a limp mode.. It did this BEFORE I installed the spacer as well. Every time I retrieve the code, it is always the knock sensor... I replaced the knock sensor, and it effected nothing, still threw a code. I inspected the wire and everything seems to be fine. So why does the CEL keep coming and why does the truck keep going into limp mode every time I go about 3/4 throttle?????? Could this be a computer malfuntion or is there something mechanically wrong with the engine? I have never heard it knock or ping AT ALL. So what could be tripping the sensor?

This all started after the guys at the tranny shop improperly adjusted my TV cable and the first time the light ever came on was a few months later when I down shifted to pass another car

 

[89Suburban]

 

[HotRodPC]

Cool, so the trans if fixed now, I was thinking and hoping that was all it was. I was bit more concerned about that problem you mentioned at one time the TCC not unlocking the converter.

So onto the Knock sensor... You say this never happened until the trans rebuild and you have replaced the sensor and didn't correct the problem.
My next guess is going to be during trans install the wire was possibly stretched or pinched. Its a bit common during trans installs at times, that a part of the loom or just a wire falls between the trans and motor and gets pinched then goes to a direct ground. I'd start at the knock sensor and follow that wire back as far as you can follow it looking for damage, bare, pinched or pulled and stetched coating on the wire.

 

[CknightK10]

I found a slight sever in the wire. So, I stripped it and crimped it. Still no difference. I heard that the knock sensor wire consists of a wire, and then a separate isolated wire in the same sheathing, similar to an RCA cable. When I striped mine it was not like this at all, it was just a simple wire. Do the later models have this isolated wire set up and my 92 wiring harness is just a solid wire?? Sorry if I am being confusing.

 

[HotRodPC]

Not confusing to me, I understand totally what you mean, but honestly, I don't know that answer to that one. Maybe with some research I can find out. Those sensor wires are fairly delicate since many read in mili volts. However I don't see the need for a knock sensor to be that way. Its either knocking or its not period., so it not like a TPS or Crankshaft sesnor. Let see if someone will chime in here on that. I gotta get ready to run and do the part time thing.

 

[89Suburban]

 

[HotRodPC]

Another thought, have you cleared the code after you fixed the wire? And you're sure its not memory code coming up???

 

[RetroC10Sport]

Unhook your battery for a minute, hook it back up, start truck and let it idle in gear for 5 minutes.

I would try a new ignition module. I've had a knock sensor code come up and it turned out to be the module.

Also check a dark blue wire that runs from the module to the sensor and a black wire that goes from the module to black 24 pin connector on the ECM, B7 cavity. Check these with a DMM.

 

[CknightK10]

I have never cleared the code with a scan tool, just unhooked the battery.

Retro, is that an idle re-learn procedure??

 

[HotRodPC]

I have never cleared the code with a scan tool, just unhooked the battery.

Retro, is that an idle re-learn procedure??

I don't think you need a scan tool to clear the code. 92 is still OBD 1.

 

[RetroC10Sport]

Retro, is that an idle re-learn procedure??

Yep.