chazman

iTrader: (4)

Also, changing the fog light bulbs was kind of a biotch. There seem to be more fairings and plastics in the way than on earlier 3rd gens - which are pretty straight forward. In the end, I had to remove the light to get a new bulb in it.

dmccain

iTrader: (2)

[QUOTE=chazman;5917782]It actually drives really nice. My butt dyno tells me it's quite a bit faster than a 16.5, though.

This is the L98 cammed LB9 with an L03 exhaust.
"My 91 Z28 Auto LB9 2.73 posi basically stock except for smog and cat delete and 2.5 exhaust surprised the hell out of me and ran a best of 14.76. I was accused of having a 350 and hustling people at the track! Lol.

chazman

iTrader: (4)

[QUOTE=dmccain;5929128]Wow, that's fast! Factory freak?

dmccain

iTrader: (2)

[QUOTE=chazman;5929142]That was in cold weather where it seemed to have a lot more pep but it ran 14.9s consistently even in summer months. This car outran Mustang 5.0 autos,454ss trucks, Ford Lightnings,late 70s corvettes and Camaros, man I had lots of fun with it.I was surprised when the next 5.0 TPI car I had ran in the 15.4s, I was so aggrevated i actually pulled it and threw in a carbed 350 vortec.

chazman

iTrader: (4)

[QUOTE=dmccain;5929392]Well, mine is certainly not in the 14's. I feel that it could use some tweaking.

chazman

iTrader: (4)

Drove at highway speeds with the top down today. Visors are perfect, (so far).

And windows work great now that I've removed that tacky window tint. That was a sticky job!

1MeanZ

iTrader: (9)

What do you use to remove the window tint glue? As terrible as it sounds, I've had the best luck with using brake fluid to melt the glue. Just curious what you used.

On your performance issues, I'd re-check ignition timing, check the TPS voltage, put a new O2 sensor in it, and see what happens. Does the check engine light ever come on? Does it start and idle OK? Are you getting good sound and flow out of the tailpipes? (Plugged cat?). I know you know all this stuff but I'm throwing it out there for anyone else reading too.

chazman

iTrader: (4)

It's some pretty powerful stuff. I check what it's called when I get home. But it dissolved the glue very effectively.


The timing is currently set at the factory setting of 6* advanced. I think I'll bump it up a few degrees.

Someone correct me if I'm wrong, but I don't think you can adjust the TPS on a Speed Density car?

Cat looks new. In fact, from the cat back looks replaced. Too bad my intermediate pipe is broken before the muffler. O2 sensor is a good idea.

chazman

iTrader: (4)

The chemical is called "1st AYD ACRYL-CLEAN SUPER CLEANER". I'm not sure where you can buy it. I got it from someone who works at a shop. It made very short work of the tint glue on the windows.

Stauf

iTrader: (2)

You may have just doubled "1st AYD"s yearly revenue. They seem to be a small company, and not easy to find their prodoct.

1MeanZ

iTrader: (9)

The Throttle Position Sensor is adjustable on all TPI cars regardless of MAF or MAP. Shoot for .54-57v at idle. (ignition on engine off) Then slowly roll the throttle open and the voltage should smoothly and linearly sweep up to about 4.5v at WOT.

TPS are a simple potentiometer. They can develop a dead spot in their range of motion due to wear. This causes the voltage they report to the ECM to be non-linear with actual throttle input and can cause stumbling, weird idle and severe hesitation. Throttle position plays a large part in how the ECM calculates engine load, which directly affects the amount of fuel delivered at any given time.

chazman

iTrader: (4)

Knowing that they are in fact adjustable, I'm going into the garage right now!

chazman

iTrader: (4)

Surprise, surprise, surprise. I went to hook up my TPS tool and saw this.


The connector to the TPS is broken and held on by adhesive and a zip tie. How did I miss that? Too busy wet sanding, I guess. Anyway, I set it to .54 which was a bit tricky, since the broken connector had to be jiggled a bit to show an accurate reading. Took it around the block. Can't say I felt any difference. Check engine light came on, disconnected battery and it seems to have cleared the code.

AmorgetRS

iTrader: (6)

How did you adjust it since it isn't slotted like the earlier ones? On speed density cars the zero point is set when you turn they key on, so it can be a wider range of values as compared to the MAF cars.

chazman

iTrader: (4)

I had trouble with it. I moved it around until it said .54 and tightened it. I didn't feel confident in the readings like I would in a MAF car.

AmorgetRS

iTrader: (6)

I'd buy a new connector for it and either re-pin (my preference) it or splice it in. IIRC it's just a standard 3 prong weatherpack, but you can buy it with pigtails at basically any auto parts store last time I checked.

chazman

iTrader: (4)

I just got an email from 1MeanZ and he's got an extra connector he's going to send to me and I'll try to re-pin it. This is the kind of thing I'd like to tidy up.

AmorgetRS

iTrader: (6)

I don't know why, but people seem to be prone to breaking them. I bought one car that was using several zip ties to hold it on.

1MeanZ

iTrader: (9)

All TPS from 85-92 are all the same on TPI engines. The sensor he shows is slotted too, but the factory washers cover the slots up in the picture.

I think it's TBI cars that re-zero the sensor at each key on.

1MeanZ

iTrader: (9)

Lol go pop the hood on the 85 or the 89, identical sensors and adjustment I promise. You've likely never needed to mess with them on your other MAF cars because they are such low mileage.

AmorgetRS

iTrader: (6)

Not according to this thread:

https://www.thirdgen.org/forums/tpi/...-straight.html

You are right on the TBI ones, they don't adjust at all (at least on my 92)

*edit* I went and checked my 1991 Firebird Formula LB9 and my TPS sensor is not slotted. See attached picture.

chazman

iTrader: (4)

Oh, I've done them both, as well as my CFI. Hey, a free mod is a free mod.

1MeanZ

iTrader: (9)

Well I learned something today. I had no idea the 91-92 TPS were different. When I had a 91 Trans Am it had a slotted TPS on it that I believed to be original, apparently it wasn't. I haven't worked on many SD cars overall, but have yet to see one with an original non adjustable TPS.

chazman

iTrader: (4)

So the consensus is, once I've fixed the broken connector - I'm done with the TPS on this car?

1MeanZ

iTrader: (9)

yes, if the later '730 SD ECM is like the TBI/truck '746/7/9 ECMs and it re-zeros itself at key on, then no adjustment is needed. Just make sure that with the key on the voltage smoothly increases with throttle opening (no dead spots).

also check the plugs on your MAP sensor, Intake Air Temp sensor, Knock Sensor, Coolant temp sensor and cooling fan temp switch in the passenger side cylinder head.

You mentioned earlier that the check engine light came on? If you haven't unhooked the battery since then pull the codes and tell us what you find.

yaj15

iTrader: (3)

How is the structural integrity on this car feel when compared to a hard top or t-top car? I've never driven a convertible thirdgen.

Also (and correct me if I'm wrong) but didn't the 1991-1992 cars get some additions at the factory to make them more solid structurally?

chazman

iTrader: (4)

Service engine light came on today. I figured it must be something to do with the TPS. The car died on me a bunch of times and I restarted. Not too much fun when you're on a 6 lane road with a semi on your butt.

Just read the code and it's 21, TPS voltage high. Checked the TPS and I'm getting .54 v but only about 2.9 V at WOT.

What's up?

AmorgetRS

iTrader: (6)

Assuming you are getting 5v at the TPS, replace the TPS.

chazman

iTrader: (4)

Do you say that because of the low WOT reading?

chazman

iTrader: (4)

Okay....I may very well need a new TPS. But I suspect my car troubles today, may be from the broken connector. I used electrical tape on the connector and used a fresh zip tie to fasten it to the TPS and the service engine soon light turned off on a spin around the neighborhood. Except for a slightly rough idle, it appears to be operating normally.

I should probably clean out the IAC as well.

Stauf

iTrader: (2)

You should be fine. You DID use a fresh zip tie.

Seriously, it sounds like a bad connector. If the connector is broken/cracked any vibration or dampness can wreak havoc on the ECM. Did you ever get a chance to replace the old connector?

AmorgetRS

iTrader: (6)

Yeah, I agree with Stauf. I had forgotten that your connector was shot.

mk1431

What is a a SD car??

AmorgetRS

iTrader: (6)

Speed Density, aka 90-92 TPI motors in this case (but also used on 90-92 V-6s and all TBI motors). 85-89 TPI motors used a MAF, or Mass Airflow Sensor. Speed Density cars use a MAP sensor, aka Manifold Absolute Pressured.

chazman

iTrader: (4)

Yes, very fresh!

On my list....

chazman

iTrader: (4)

What do you make of the low WOT reading, then? And why would I get a code for high voltage?

chazman

iTrader: (4)

They had structural adhesives and I do believe they feel more rigid than earlier ones without it.

yaj15

iTrader: (3)

That's good. I always wondered about that since what I've read said that was a precursor to some of the structural adhesives that they used in the 4th gen cars.

That's a really cool car. I haven't seen another purple haze '92 drop top before in person. For that matter I can count on one hand the number of purple haze Z28's that I have seen in person.

Are you going to put the factory N10 dual cat exhaust on that car? Would be a cool sleeper since you've got the G92 cam.

AmorgetRS

iTrader: (6)

Unfortunately I don't know. In this case since you for sure have a problem with the connector, I'd start there. Once that issue is resolved, I'd move onto the TPS.

Just curious, are you checking the voltage at the ECM or at the TPS? If only the TPS, it would be interesting to see what the ECM is seeing for voltage.

1MeanZ

iTrader: (9)

I just came in from working on the black car Charlie. I'll pull a TPS connector out of my box tomorrow (I think I have a couple) and get it in the mail to you. I'll also swing by NAPA and look into the de-pinning tool and see if I can at least get you part number to order.

Usually when TPS fail, they get a dead spot in them. You having low voltage at WOT does not sound like a normal failure path for a TPS, but I agree with the others, put a new connector on and see what happens.

AmorgetRS is right, 5v at the sensor is critical as well. If you don't have that, you need to address that first.

AmorgetRS

iTrader: (6)

For de-pinning I personally use this one:

mk1431

Thanks

chazman

iTrader: (4)

The center cap fairy came today. I met my friend's friend at a cruise night a couple of weeks ago, and after checking out my car, he asked me if I wanted some center cap he still had in his garage.



Only three, but much nicer than the ones I had on the car.

PurelyPMD

iTrader: (3)

Those look pretty nice Chaz!

chazman

iTrader: (4)

And can't beat the price!

Stauf

iTrader: (2)

Yeah.. I ordered 4 from HubCaps.com at $45 each. The quailty was much less then I expected, and they were promptly returned. Wish I could find someone who just had some mint NOS ones lying around. You made out great on that deal.

chazman

iTrader: (4)

They guy who gave them to me had an incredible '69 Chevelle. This car was painstakingly restored stock. It was a 4 speed, big block car in Butternut Yellow. After a few years, he got bored with the way it drove, and built a supercharged 6.0L LSx motor with a Tremec 6 speed. I'd usually frown upon something like that, but this build was incredible. He is an engineer and a former GM tech. He re-engineered the accessories, pullies, hoses, every thing, to look like something GM would put there from the factory. One of the best ones I've ever seen. Plus he still has the factory drive train tucked away in case he ever changes his mind. Oh, by the way, it's docile enough to use as a daily driver, but can dip into the 10's with proper traction.

PurelyPMD

iTrader: (3)

I was given 4 NOS ones when I picked up my 91 - all but one of the ones on the car were perfect & I happened to have a clean original in my tool box from 20+ years ago.

chazman

iTrader: (4)

Quick updates. Bumped up the timing a few degrees, car feels more perky. Was able to find an original TV cable through the GM dealer, since I don't trust the aftermarket one on it and having it installed today. Got the TPS connector from Jeremy, (thanks!) yesterday. De-pinning it is on my list.

Gotta go...

two-if-by-sea

iTrader: (22)

Is there any difference between the thirdgen caps, and the fourth gen "salad shooter" caps? I know the CAMARO font changed between third and fourth gen, but I've not paid much attention to 4th gens in the boneyards.