Hey guys. I had Alvin@PCMforless burn me a custom prom for my car, and it's causing a strange problem with the 2-3 shift in my 700r4. I haven't the foggiest idea when it comes to tuning a chip myself, hence the reason for using PCMforless. Let me lay out the symptoms for you guys and see if you have any idea how the custom prom could cause this. Whenever I have the custom prom in the ecm, if I'm giving the car moderate to heavy throttle there's a consistent fluctuation, or flare in 2nd gear around 4000 rpm. It'll jump up a couple hundred rpms, then when it shifts to 3rd the motor bogs and the shift is rough. Strangely enough, whenever I put a factory chip back in the ecm, the 2-3 shift is perfect, with no fluctuation and a firm, quick shift into 3rd. The trans was just rebuilt with Dana's street/strip kit, including his modified TransGo shift kit, vette servo, 2600 stall, etc. And since it shifts perfectly with a factory prom, I think I can safely say it's nothing mechanically wrong with the trans. It only shifts funky with the custom chip in the ecm. My limited understanding is that the ecm supposedly has no effect on the trans except for the lockup speed when in 3rd or OD. But lockup speed or maybe the 2-3 pressure sensor in the valve body are about the only reasons I could come up with for my problem. Yet it works perfectly simply by swapping a factory prom back in the ecm. I had to go with a custom prom since I'm running 24lb. SVO's, AFR heads, Super Ram, sizable cam, etc. It idles terribly with a factory prom and likes to stall when you put it in gear, yet is shifts beautifully. With the custom prom the idle is perfect, acceleration is great, but the 2-3 shift goes to hell for some reason. Btw, my setup is an 89 '165 system if that makes any difference. Do you guys have any idea what part of the tuning tables could be causing this? I've emailed Alvin already, but he usually takes about a week to reply back, so I figured I'd pick you guys' brains in the meantime. Any insight or advice is greatly appreciated as always! in advance!

 

1st question.. Is your car a 1991 with a 700r4 electronic transmission with an electronic transmission control module? If it isn't, it only uses one electronic plug-in that is for the torque convertor and it is lockup. It won't control shifts between 1 and 2 or 2 and 3. If your have a newer style transmission I believe it is called a 700r4e model. Then it would control the shifts. Unless your TCC is locking up, it can be controlled in the chip. I have rarely ever found any company that can produce the magic chip that makes a car run 100% the 1st time no matter who they are.

 

You could try removing the wire for the lockup and running it to see if that solves it.
You may/may not want to just "unplug it" because of the 4th gear switch indicator is also included on the plug.

 

It's an 89 700r4, so there's definitely no electronic module of any sort that could be affecting the shifts. I just received a reply back from Alvin, and naturally he says there's nothing he can change in the prom since the only thing it controls is the lockup function, which I already basically knew. He said now that the car is producing more power that maybe the trans isn't able to hold the power. That can't be the case though since it's just been redone with Dana's street/strip kit and it holds and shifts perfectly with a stock prom. Also, the 2nd gear flare occurs every time at the exact same rpm, and only when Alvin's chip is in the ecm. I wonder if the timing tables might be off in his chip. Maybe it's not getting the proper amount of advance or retard? Maybe something in the MAF tables? Hell if I know. I'll try what JP suggested and unplug the lockup wiring temporarily to see if it changes anything. I was thinking of trying that anyways. If it does, I guess I could get an aftermarket lockup kit and try to remedy it that way. If all else fails, I guess I'll just throw in the towel on trying to use the 700r4. I have a TKO 5 speed all ready to go sitting in the garage. Since the car is my daily driver, I just hate to convert it to a stick. It's way more convenient to have the auto, makes it easier to drink my coffee on the way to work in the morning!

 

You should send back the prom and have him check it ... Alvin is from PCM for less right? he does work for Trailblazer owners, and as of my last visit to the forum he has a pristine reputation, so I'm sure he'll check it for you...

 

Yeah it's Alvin from PCMforless. He basically told me there's nothing he can change, but I think I'm gonna bug him a little more because I honestly think it has something to do with the lockup control. I just got off the phone with my trans builder and he said the converter can actually engage lockup even in 2nd gear sometimes, and he's thinking that little flare up right before it shifts into 3rd is the lockup either engaging or disengaging for just a second. That makes sense to me. I appreciate the help from you guys so far!

 

Well I just emailed Alvin again and asked him if he could at least go back into the bin and check the lockup settings, so we'll see if he lives up to his reputation. I also told him I can send him my other stock prom that works the trans perfectly, so that he can compare its settings to the settings in his prom. My trans guy said we could always put an aftermarket lockup kit in the trans, which I've already been considering, but I'd really prefer to retain the factory lockup control if at all possible. All the aftermarket kits have their drawbacks compared to the original setup. I mean even my Hypercrap chip controls it properly, so I would think someone as supposedly good at tuning as he's supposed to be would be able to get this straightened out. We shall see.

 

Hey guys, another quick update. I talked to Dana from ProBuilt on the phone last night, and he said he's about 99% sure the bog/rpm drop when it shifts into 3rd is because the converter is either already locked when it goes into 3rd, or it's locking up immediately after the shift, even though I'm still heavy into the throttle. Alvin is still arguing with me that it can't possibly be the lockup settings. If this is the case, then why would it be that the ONLY thing I change between test runs is the prom and then the 3rd gear shift and the lockup function are both perfect? The stock chips make it idle unstable and pig rich, due to the larger injectors, and you can feel that the power curve is definitely more lackluster, but the 3rd gear shift is just BAM!, quick and crisp with no rpm bog. When I told Alvin I'm going to send the stock chip in along with his so he can compare the lockup settings in the bin, he gave me a curt reply saying "send in whatever you like, but I don't think it's the problem". Man, I gotta agree with you guys that doing your own tunes is hands down the best way to go! I swear when I have the time/patience to start doing my own, life will be much better. Dana referred me to Ed Wright @FastChip if I can't get this straightened out, but hell that's another $350, and I've already got over $200 invested in Alvin's tune. Lesson learned, I think my next $300 investment will be an Autoprom from Moates and the Tunerpro software! I'm a neanderthal when it comes to computers (beats on keyboard with cloven hoof), but since you'd have to pry my 3rd gen out of my cold, dead hands I guess it's time to learn! Either that or save up the money and see if I can find a local shop that can do a dyno tune.

 

Best thing to verify it would be to do a datalog of the data and see if its turning on. Can't argue the point then.
For now, see if you can "tighten up" the TV cable 1 click to keep it in second gear a bit longer. Might help the stumble, may make it downshift too quickly. Will have to play with it.
Its tricky once you start to use the TV to control the shifts though. Just be sure to not go too loose of an adjustment when on the throttle because low pressure from the cable not being pulled can kill the forward clutches and the 3-4 pack with power applied.

 

I have been tuning my own car for a while now. I thought at one time going to a preprogrammed chip would be easiest,.. Wrong!! By the time you keep trying to explain what is wrong and sending the chip back and forth to get it burned.. It just isn't worth it. You are on the right track on the self tuning.

 

Can it have anything to do with the iac
settings in the chip

 

Doesn't sound so. The IAC (Idle Air Control) should be around 160 - 255 on startup then drop to around 0 - 50 while running after engine warms up usually within 2 minutes. The IAC doesn't have any effect on the transmission. You can check this with any datalogger, or quality scan tool

 

Yeah, as far as the IAC goes, it works fine until I have the stock chip in there. With the larger injectors it runs way too rich at idle, and you can hear the IAC going nuts trying to keep the idle steady! When the custom chip is in there that's set correctly for the 24's it idles steady as a rock. Hey JP, I've definitely already worked through any TV cable issues. It was an incredible PITA to get the geometry correct on it with the Super Ram intake! I finally bought a shorter wire link made by Sonnax that goes between the trans end of the cable and the bellcrank/plunger assembly. That gave me significantly more adjustment up at the throttle linkage and got the pressures and shift points where they need to be. Adjusting it one click tighter makes it shift a bit later and a bit firmer of course, but that little rpm flare is there no matter where the cable is set, which leads me to believe that it's the converter unlocking. It only flares about 200 rpm, which is consistent with the converter unlocking. Besides that, it doesn't flare at all with the stock prom and no change in the TV adjustment. And if it's locking back up right after the shift into 3rd that would totally explain the bog. Actually now that I think about it, the rpms drop back down right before the 3rd gear shift, so I'm betting it's already locked when it goes into 3rd. I did convince Alvin to check both chips and compare the lockup settings, so I'm gonna mail them back to him tomorrow. Wish me luck guys! On the plus side, the brand new motor runs beautifully, and the newly rebuilt 700r4 works perfect when the prom isn't wreaking havoc with it, so if I can just get this one little glitch remedied, the car should be a blast to drive!

 

Is the car noticeably faster with the custom prom? The best explanation to me, would be it's making more power and the trans can't hold the shift. But I see it was recently rebuilt. This is a weird one. I'm no tuning expert, but I agree there's nothing I have ran into that would cause a shift flare in the chip. I don't even see how a converter could cause a slip/flare.

As far as Ed wright, I'm pretty sure he'd tell you the same thing that Alvin is telling you.

Keep us updated! Good luck.

 

Thanks for the input! Naturally it does pull harder with the custom prom, but not like night and day harder. What's leading me to believe it has something to do with the lockup control is not only the little flare, but what really makes me think that's the culprit is how it drops and bogs when it shifts into 3rd. As Dana said, it sounds like the converter is already locked when it shifts to 3rd, which would definitely cause a bigger drop in rpm, causing it to kinda lug or bog. As stated above, it doesn't flare or shift funky with a stock prom, so I just keep going back to thinking that the lockup has to be kicking on and off at the wrong times with the custom prom. I'm gonna try unplugging the lockup wiring down at the trans with the custom prom in the ecm and see what happens. I figure I better do a little more troubleshooting before I jump the gun and end up sending the prom back for nothing. I was gonna try that today, but it's friggin snowing outside!! That'll definitely cause a "slip" when the tires break loose on the snowy roads! Lol. I agree it's a strange problem, and it confounds me that simply changing the prom and not touching anything else makes the tranny shift perfectly! I mean, ideally, when the car is under heavy throttle the damn lockup shouldn't even be engaged at all. And if it was actually a legitimate slip it'd be doing it in every gear I would think. It occurs at the exact same rpm every time and always in 2nd gear right before the shift to 3rd. It'll be at 4K, you'll watch the tach spike up to about 4200 for a split second, then drop back down to 4K, then when it shifts to 3rd, just blah. All of this goes away with the prom change. I'll post back up after a little more checking. Gotta wait for the stupid weather to clear up!

 

Hey guys, another update. I decided to do some more research before sending the chip back and I stumbled across some interesting info on how the lockup wiring is set up. My 700r4 was from a TBI f-body originally, and after checking the wiring diagrams in the factory shop manual I noticed it's wired differently from the TPI 700r4's. The TPI lockup uses a NO (normally open) 4th gear pressure switch, and the converter lockup control switch in the ecm is also NO. The TBI uses a NC (normally closed) 4th PSI switch, and the converter lockup switch in the ecm is also NC. In addition to that, the TBI 700r4 also incorporates a temperature switch that engages lockup if the trans fluid gets too hot, whereas the TPI 700r4 doesn't have the temp switch. So in light of that info, I dropped the trans pan, eliminated the temp switch, and replaced the TBI 4th gear PSI switch with a TPI switch. I have a spare 700r4 on the back porch that came out of a 91 5.7 TPI car, so I snagged the PSI switch and lockup harness out of it and put it in the TBI trans. Now I just gotta go to the parts store and pick up another pan gasket and put everything back together so I can see if it makes any difference. I'm starting to think this damn thread should probably be in the trans forum instead of here! If this actually ends up fixing the problem, this would be great info for anyone who converts their TBI car to TPI with a 700r4. I'll post back up with the results.

 

There is a flag/switch in the calibration to define whether the 4th gear switch is NO or NC. By your description of the problem it would appear that the stock PROM is set correctly while the "purchased" chip is not.

This is one of the reasons that we do our own tuning.

RBob.

 

Pat, thats a lockup malfunction in the aftermarket code. The first thing you want to do is ask Alvin if he burned you a prom setup for a manual transmission, as if this is the case, it will throw the VSS feed for a loop, and once 40-mph is realized the torque converter will engage, then disengage, repeatedly (causing your RPM fluctuation, and poor shift response). Either that, or the new prom and the stock VSS sensor might have a difference of opinion....

 

Oh believe me RBob, your point regarding self-tuning is very well noted here! After spending over $200 for his tune, I'd send him an email with a complete, detailed description of the symptoms and what I've tried so far to eliminate the problem, and all I get is a one or two sentence reply saying "Send it back if you like, but I don't think it's the problem". Nice huh? No tips, advice, suggestions, NADA. Probably just too busy to bother with someone who's already paid for a chip. Now for my update. I think I actually fixed it!! I took the 4th PSI switch and TCC solenoid harness out of the TPI 700r4 that was sitting on the back porch and installed it in my trans, and Wahlah! No more 2nd gear flare/spike, and the shift into 3rd is quick, firm, with no more bog! I think eventually I'll redo my lockup per instructions here on the site to where I can manually engage it ONLY in 4th. With the cam and converter I'm running now, I think that'll keep the motor in its power range better rpm-wise. Freeway trips are about the only time it really needs to be locked up now. Believe me though, that's the 1st and the last mail order chip I'll ever buy! Next big purchase will be from Craig Moates! The mail order chip at least served the purpose of being able to get the car running halfway decent though. I know learning how to do my own tunes is going to take a lot of time and patience. I'm great at wrenching, but basically retarded when it comes to computer stuff! Thanks everyone for all your tips and advice. If I hadn't searched the boards here thoroughly, I don't think I would've ever figured out the lockup circuitry was different between TBI and TPI.

 

For lock up only in 4th, this can be done in the calibration. Once you get the required pieces for tuning it will be easier then changing/running additional wiring.

You will also be able to change the lockup points to suit the rear ratio, torque converter, and engine power band.

RBob.

 

FWIW my '89 Caprice (9C1 w/ L05) only locks up in 4th gear.

 

Well guys, I jumped the gun saying it was actually fixed! The 2nd gear flare/spike is gone, and the shift into 3rd is definitely better, however it still locks up pretty quick after the 3rd gear shift, even though I'm still heavy on the gas. I have to agree with Street Lethal and RBob, I think the problem is still related to the lockup settings in the prom. So I'm off to the post office tomorrow to mail the chip back to Alvin. I don't regret dropping the trans pan though. At least the lockup wiring is all correct for TPI now, and my pan gasket was leaking too. My rebuilder put one of those pathetic, paper-thin gaskets on the pan. I replaced it with a nice, thick rubber one from Fel-Pro. I'll post again when I get the chip back from Alvin and try it out. Again, thanks to everyone for the help so far!

 

You may be hitting the forced lockup MPH. Stock is somewhere around 76 MPH.

RBob.

 

That could be a possibility too. I'm probably right around that MPH when it locks up on me. I'm guessing the forced lockup engages even if you're still into the throttle right? Because I know that normally the converter won't lockup unless you're only lightly on the throttle or at a steady cruise speed. I've seriously been considering just rigging my lockup to a toggle switch, but then again I hate to "afro-engineer" my lockup when I'm almost sure it's a problem with the custom chip. Solving it that way seems kinda backwards to me considering it functions properly with the stock chip. Wow, this site lets me type "afro-engineer", but it censored "r edneck". Lol.

 

We are back to where it comes down to getting your own stuff to burn and DIY. Everything is adjustable and only takes but a minute to change. There is a lot to be gained driveability wise in doing the TCC lockup tables yourself.

For how it all works head up to Chapter 5 of the Tuning Guide Book sticky. The section on '8063/'7747/'8746 ECMs has a write up on the TCC logic.

My only warning is that DIY_PROM tuning is extremely addicting. Could easily be classified as a narcotic by the DEA.

RBob.

 

Hey guys, just wanted to update the post and let you know it's finally straightened out! 85MikeTpi offered to look at the chip if I mailed it to him. It turns out that Alvin basically used the ARAP bin for my tune. Mike compared the ARAP TCC settings with my 89 AUJL bin, and they're quite a bit different from each other. He burned a copy of Alvin's chip with the AUJL TCC settings grafted on, and it works fantastic now! All the shifts are lightning quick now, no bogging at all, and the lockup is finally working exactly like it should. I can definitely say I learned my lesson about relying on a mail order tune! I've already downloaded TunerPro RT and as soon as my tax return shows up I'm purchasing an Autoprom from Moates. I've always made a point of learning how to do all my own mechanical work, and now it's time to take the same approach to tuning. I owe a huge to Mike for the help. I'm simply too broke at the moment to purchase the tuning equipment, but rest assured I'll be buying it as soon as I have the money set aside!

 

I bet it was the TCC lockup threshold. it will lock up at a certain mph under ANY throttle condition. ARAP locks at 76mph and AUJL locks at 88mph. For what its worth my car ran faster with the converter unlocked at WOT. Just set the bin mph to something high like 150mph.

If you dyno the car, set it to like 50 to put down the true hp/tq numbers.

 

Hey thanks for the tip Orr. When I was looking at the bins in TP I noticed there's like 4 or 6 different TCC tables to adjust, and I wasn't quite sure which one does what.

 

Any idea what that would be called in $32b?

 

Thing I see that looks like it is TCC unlock prevent/Auto O/D engage constant. In 6E is called similar, Tcc unlock prevention threshold

Both my bolt on L98 and 383 ran best with the converter open during WOT in the 1/4 mile. On the dyno you can gain (or show on your graph) lots of torque and power. 15wtq/whp on my L98 all over the range. Some GTO's at our recent dyno tune day gained like 30wtq across the board on the dyno with it locked. Doesnt mean you will run faster at the track tho. I never did and I tried locking it at several different speeds

 

Drove it to work today and then all over town running errands later. Man, it sure is nice to have it function like a normal car again! Up until now it's been one issue after another ever since I yanked the tired old L03 out and replaced it with the Super-Rammed 355 and the fresh Pro-Built 700r4. My cooling fans were another thing that were acting crazy. They'd run as soon as I started the car, with the motor being cold as ice. I bypassed the ecm controlling them for now by putting in the Hayden 3647 adjustable fan control unit. Works fantastic! Once I get the Autoprom and get more familiar with chip editing, I'll try running them through the ECM again. I've read in posts on here that there's a flag switch in the bin that needs to be either checked or unchecked to solve the problem of a constant running fan. I wired the Hayden control to kick both fans on at the same time, so it cools down nice and fast! It's great to be able to adjust the on/off temps with the simple turn of a screw.

 

I think its something to do with the fan wiring that causes the fans to run at startup when using ARAP bin. Vettes used ARAP and the fan wiring on those cars i do believe are different than fbodys. I ran ARAP on my car and had the same problem, fans turned on immediately. I went back to AUJL which is the stock 89 350 bin for my car and it worked normal again.

 

The fan relays are set up differently. On the relays there are two sets of contacts. One set is normally open (NO), and the other set is normally closed (NC). When the relay is activated the contacts change position. The NO set then closes and the NC set opens.

The f-body uses NO while the y-body is NC. So a y-body calibration turns on the relay to turn off the fan. With a y-body cal in an f-body, it does the opposite and turns on the fan when commanded to be off.

There is an option flag in the calibration to change this action.

RBob.

 

Yep, good old AUJL! That's the same bin I use for my base/backup tune, and my fans worked right with it too. That's also the bin 85MikeTpi used to fix the lockup settings on my ARAP based custom tune. I concur with you RBob, the flag you check/uncheck is what I was referring to when I said I'd read up on it in previous posts. Like you mentioned above, the ARAP bin makes the fans in our f-bodies work the opposite of what they should until the flag switch is reversed in the bin. Member King89Iroc from Sweden posted a while back with the same issue. I also have to agree about self-tuning being classified as a narcotic. Lol. Even though I haven't bought the Autoprom yet, just looking at my bins in TunerPro, my fingers are already itching to start tweaking stuff! My new motor seems to agree nicely with the ARAP timing tables though. Running AFR 190's and about 10.2 CR. Yesterday I set the base timing to 8 degrees, and adjusted the TPS voltage and minimum idle screw, and the acceleration/power curve is pretty damn impressive! Once I got those TCC tables straightened out, everything else is falling right into line now. With me being such a greenhorn on the EFI stuff I gotta admit I'm really appreciating the simplicity and adaptability of the '165 MAF system.