Cheesehead
Member
- Joined
- Jun 25, 2001
Here's a copy of an email that I just sent to Ken Mosher. Any suggestions from you guys would also be greatly appreciated.
Subject: Strange Voltage Readings on TLink
Thanks for the reply.
I've checked the grounds with an ohm meter to other areas on both the block and
firewall and also tested the TLink cable from the ALDL end thru to the parallel
cable end with an ohm meter--the outer two prongs on the ALDL end test thru to
two pins on the parallel cable end without any apparent shorts to any other pins.
I couldn't find a pin with continuity back thru to the center prong on the ALDL
end. The laptop that I an using is a Packard Bell PB286LT.
I'm attaching an ECM file so that you can see what I am talking about.
I was having the same surging/backfiring problem with the original '85
ECM/MAF/CalPack/Caspers 8-Position Chip. All of these items were replaced this
weekend along with a new MAT with wiring harness so that I could have the benefit
of more data from TLink. I have lots of data now, but I'm still baffled. Could
the alternator be failing?
If the surging/backfiring problems aren't related to the voltage problem, do you
think that the wastegate solenoid could be failing?
Sorry for the long message, but I've been struggling with this for a long time and
don't know what else to try.
Ken Mosher wrote:
> "M. Rogers" wrote:
> >
> > I purchased TLink this spring and have just upgraded my 85GN to the 87
> > ECM/MAF/MAT so that I can see more scan data.
> > My problem is that the voltage readout on TLink will occasionally drop
> > as low as 1 volt and jump as high as 19.2 volts. Also, TLink
> > periodically detects and then clears various malfunction codes.
>
> Those are symptoms of grounding problems, usually. A good first place
> to check is the grounds on the back of the passenger's side head ...
> they often get brittle with age/heat and cause all sorts of wierdness.
>
> Also, check the ALDL ground wire to make sure it is still making good
> contact. If you continue to have problems, I'd be happy to check the
> cable out on the test bench (just to make sure we don't have something a
> little loose or marginal in the cable). Just send it to the Colorado address:
>
> Ken Mosher
> 4209 Trailview Lane
> Fort Collins, CO 80526
>
> with a few bucks to cover return shipping, and I'll check it out for you.
> >
> > I am having an awful problem trying to tune this car. It idles great
> > and will accelerate ok if I depress the throttle slowly. If I floor it,
> > the car will start surging (back-firing ?) when the boost comes on. I
> > have a Jay Carter 93 octane street chip. Have tried adjusting the fuel
> > pressure from 40 to 46 #'s. Have also tried adjusting the boost from 14
> > to 20 #'s. The BLM's consistently are higher than 128 even at
> > extremely high FP settings. I can't get any WOT readings because of the
> > way it runs.
> >
> > Any suggestions?
>
> Boy, that sure sounds like some sort of vacuum leak or unmetered air
> problem. Have you tried another MAF? Does the MAF hose have some holes
> in it (especially look at the bottom side)?
Subject: Strange Voltage Readings on TLink
Thanks for the reply.
I've checked the grounds with an ohm meter to other areas on both the block and
firewall and also tested the TLink cable from the ALDL end thru to the parallel
cable end with an ohm meter--the outer two prongs on the ALDL end test thru to
two pins on the parallel cable end without any apparent shorts to any other pins.
I couldn't find a pin with continuity back thru to the center prong on the ALDL
end. The laptop that I an using is a Packard Bell PB286LT.
I'm attaching an ECM file so that you can see what I am talking about.
I was having the same surging/backfiring problem with the original '85
ECM/MAF/CalPack/Caspers 8-Position Chip. All of these items were replaced this
weekend along with a new MAT with wiring harness so that I could have the benefit
of more data from TLink. I have lots of data now, but I'm still baffled. Could
the alternator be failing?
If the surging/backfiring problems aren't related to the voltage problem, do you
think that the wastegate solenoid could be failing?
Sorry for the long message, but I've been struggling with this for a long time and
don't know what else to try.
Ken Mosher wrote:
> "M. Rogers" wrote:
> >
> > I purchased TLink this spring and have just upgraded my 85GN to the 87
> > ECM/MAF/MAT so that I can see more scan data.
> > My problem is that the voltage readout on TLink will occasionally drop
> > as low as 1 volt and jump as high as 19.2 volts. Also, TLink
> > periodically detects and then clears various malfunction codes.
>
> Those are symptoms of grounding problems, usually. A good first place
> to check is the grounds on the back of the passenger's side head ...
> they often get brittle with age/heat and cause all sorts of wierdness.
>
> Also, check the ALDL ground wire to make sure it is still making good
> contact. If you continue to have problems, I'd be happy to check the
> cable out on the test bench (just to make sure we don't have something a
> little loose or marginal in the cable). Just send it to the Colorado address:
>
> Ken Mosher
> 4209 Trailview Lane
> Fort Collins, CO 80526
>
> with a few bucks to cover return shipping, and I'll check it out for you.
> >
> > I am having an awful problem trying to tune this car. It idles great
> > and will accelerate ok if I depress the throttle slowly. If I floor it,
> > the car will start surging (back-firing ?) when the boost comes on. I
> > have a Jay Carter 93 octane street chip. Have tried adjusting the fuel
> > pressure from 40 to 46 #'s. Have also tried adjusting the boost from 14
> > to 20 #'s. The BLM's consistently are higher than 128 even at
> > extremely high FP settings. I can't get any WOT readings because of the
> > way it runs.
> >
> > Any suggestions?
>
> Boy, that sure sounds like some sort of vacuum leak or unmetered air
> problem. Have you tried another MAF? Does the MAF hose have some holes
> in it (especially look at the bottom side)?
