IHADAV8.com - Turbo Buick Tech, and Nonsense
General => New Member Introductions and Welcomes! => Topic started by: Scoobum on August 24 2016, 10:34:22 PM
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Mike is from Ottawa Ontario...and has a few issues with his car. Steve and the boys will sort it out.
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Hell...you are the go to guy around here!
Don't let him fool you, Mike! Brad knows his stuff :)
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I'll need some help on this one.
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Hi everyone. As Scooby (can I call you Brad?) said, I'm from Ottawa (Barrhaven). Scooby thanks for inviting me to the club. My 87 GN, the "darkryd" has been in the family since it was bought in 87. Never seen the winter. I took it over from my brother in 2011 who took it over from my Dad in 2001.
I've been exercising a hesitation demon. Scooby Doo has been generous to provide advice/direction. Where I'm at now is swapping in known good parts. Starting with MAF and ECM. Also replacing the O2 with a Denso. Powerlogger files are posted on turbobuick.com . parts are being shipped from a few members of turbobuick from the US. [size=78%]http://turbobuick.com/threads/hesitation-stumble-at-various-throttle-positions.443100/page-2#post-3690547[/size]
Looking forward to learning and contribute where I can.
Cheers,
Mike
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Steve...have a look at the thread...and download the PL files. MAF is spikey. Anything that it would correlate with?
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did he load the files....what was it? wheel spin that used to make spikes on launch?
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Hey Steve - the thread referred to is here: http://turbobuick.com/threads/hesitation-stumble-at-various-throttle-positions.443100/ (http://turbobuick.com/threads/hesitation-stumble-at-various-throttle-positions.443100/)
let me know if you'd like me to post files here as well.
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What maf are you running? Factory or Translator? And what chip Not knowing what I should set the chip/maf selection toin PL makes it hard for me to know what numbers I am really looking at :)
the car is adding a lot of fuel at idle, then the maf spikes, the injector pulses go way up, the blm looks more normal at that time....then it comes down a sample or two later, and goes way back.
No matter what maf it is, what happens when you tap on it with the handle of a screw driver? I am guessing either the maf is flaky or there is a bad electrical connection that is causing all these spikes to the various parameters
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Steve...it's a KB chip...stock MAF.
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Factory MAF. I've heard of the LT1 MAF and translator. I'll likely evolve to that in the future once this is resolved. I have two Known Good MAFs ordered from some good guys on tubobuicks. Coming from the US. I also have a Known Good ECM coming soon.
The chip is old. Kenne-Bell KB9007PR chip.
As you say in your vortexbuick site, "what changed" before the issue happened. I took the car to a garage to have an exhaust leak inspected. The exhaust leak was sealed at the manifold and turbo. The turbo was removed to fix the seal. Then the hesitation started. So... something may have been knocked or broken during that work. Since it looks like something electrical, I asked the garage to look at the grounds as well (as pointed out on vortexbuicks site). Update on that is pending.
The garage removed the MAF but the symptoms persisted.
I also asked them to perform the Trouble Code 45 procedure to see if it leads to a bad ECM.
We are ordering the Denso O2 as well. We recently installed the NGK O2 but everyone says Denso is the way to go.
The only other thing that I can think of is I replaced the fuel tank and pump last year. Its a Holley 12-900. After it was installed in 2015 I had some fuel leaks but they were fixed. Too much pressure on the old lines. Then this year when we started investigating the hesitation, the garage checked the fuel pressure and it was at 80 psi. A new fuel pressure regulator was installed and that resolved that problem... <edit> resolved the problem related to the high fuel pressure.
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As I said, tap on the maf and see if anything changes.
Check the ground cable going to the turbo support cable and see if it is tightly connected with the bolt to the bracket/engine.
For a stock maf, I would wonder why the maf is reading 23 at idle instead of the correct 4-6. I am guessing that that is why the blms are so low. And when the maf spikes, then the injector pulses should up as one would expect and the blms go to a more normal reading. Also, it pulls timing out of the ecm just like it thinks the pedal has been mashed even tho the tps has not changed.
And go ahead and do yourself a favor. Order a modern TT chip. I think I finally threw my bag of KB chips away. The high timing they used blew many a hg and they were really crude by today's standards :)
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Check the wiring to the MAF I had to repin my connector wire looked intact but was broken.
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Check the wiring to the MAF I had to repin my connector wire looked intact but was broken.
that sounds like the best idea! :)
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Mike,
I have a bunch of OEM parts I'd bought for my Buick (demod) before I (luckily) sold it this Spring; you are welcome to borrow/buy what you need. I am not overly free these days what with getting ready for Drag Week - but, I am sure I can offer you some help/guidance. I will shoot you a PM with my number/address.
Cheers,
Michael
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Hey Michael - its great to meet you. Glad that you're local. Currently the GN is at Wicked Garage out in Greely. They've been doing the work. I don't think its driveable though.
Anyways, i'll call you either later today or tomorrow to discuss further.
Cheers,
Mike
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MAF is on the way from TurboKeith (turbobuicks forum). Another MAF and ECM are also on the way. I will head to Wicked Garage with my laptop and powerlogger and tap :068: the MAF a bit. See if we get any strange readings. Will post once I get them. Might be later today if I can get out of work early. Otherwise early next week.
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Make sure it has at least one screen in it and that the maf is not necked down inside. Also be sure to check those wires in the connector to make sure they are firmly attached to the pins as Larry mentioned
I'm still wondering why my PL showed the maf readings in the 20's instead of 4-6 at idle.
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When I looked at Mikes PL files a couple of weeks ago, what stood out was the 'spikey' MAF readings. A lot of times I compare my own files to others to get an answer as to what's going on. My best guess is his MAF is crapping out.
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Do you see the same maf numbers as me?
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Good evening. I was able to get out of work early and do the "MAF Tap" test. I also did a few more runs with PowerLogger. http://turbobuick.com/threads/hesitation-stumble-at-various-throttle-positions.443100/page-2 (http://turbobuick.com/threads/hesitation-stumble-at-various-throttle-positions.443100/page-2)
You can see my updates on the other thread. Not sure if you guys want me to be posting here or turbobuicks.co m. Let me know. I thought I'd continue the thread there but I can transition here. Good either way.
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When I looked at Mikes PL files a couple of weeks ago, what stood out was the 'spikey' MAF readings. A lot of times I compare my own files to others to get an answer as to what's going on. My best guess is his MAF is crapping out.
"Spikey Mikey"... i'm sure i was called that as a kid growing up. The MAF tap created spikes. I uploaded the PL file to the turbobuick thread.
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Make sure it has at least one screen in it and that the maf is not necked down inside. Also be sure to check those wires in the connector to make sure they are firmly attached to the pins as Larry mentioned
I'm still wondering why my PL showed the maf readings in the 20's instead of 4-6 at idle.
there will be two screens coming with this particular MAF. Not sure what you mean by "necked down inside". do you mean nicked? Like if the screen has nicks? I need to figure out how to confirm fi the wires in the connector are firmly attached to the pins. Thats still outstanding to confirm.
The PL readings spike to the 20's but when its not spiking its around 7. higher than 4-6 but as you mention on vortexbuicks, it could be idling at around 7 if the rpms are higher. Thing is, i see rpms around 650-700 at idle. not 800-850.
I posted updated PL files on the turbobuick thread. The MAF tap (with screwdriver handle) created spikes.
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If this is an original maf you are wasting your time with it. There is a reason just about every turbo Buick you see that is driven has a translator and a newer style maf. The originals have lived their life cycle.
Added: After reading Steve input, I'm also willing to bet this maf doesn't make it to 255 @wot either. The translator is hard to swallow at $200 but you only have to buy it once. Worth it in aggravation. Then you use commonly available mafs you can get at a wrecking yard for a pittance. Or new or rebuilt ones for cheap compared unreliable stock ones.
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Make sure it has at least one screen in it and that the maf is not necked down inside. Also be sure to check those wires in the connector to make sure they are firmly attached to the pins as Larry mentioned
I'm still wondering why my PL showed the maf readings in the 20's instead of 4-6 at idle.
there will be two screens coming with this particular MAF. Not sure what you mean by "necked down inside". do you mean nicked? Like if the screen has nicks? I need to figure out how to confirm fi the wires in the connector are firmly attached to the pins. Thats still outstanding to confirm.
The PL readings spike to the 20's but when its not spiking its around 7. higher than 4-6 but as you mention on vortexbuicks, it could be idling at around 7 if the rpms are higher. Thing is, i see rpms around 650-700 at idle. not 800-850.
I posted updated PL files on the turbobuick thread. The MAF tap (with screwdriver handle) created spikes.
Okay, if the maf numbers spike when you tap on it, that is a sign of a bad maf. That means that if you hit a bump in the road it will change the fueling drastically... but even a vibration of the maf will cause it to spike. The tap test is the classic, simplest way to test a factory style maf on our cars. In 99.9% of the cases, the maf is bad. In the other 0.01% of the cases, it might be Larry's connector problem because these cars are 30 years old and the connectors are beginning to fail.
Now, to test a connector, hold the connector in one hand. Then with the other hand, tug gently on each individual wire and see if it pulls back from the connector meaning that the pin is not crimped to the wire properly any more. While you can find someone with a weather pak connector wire tool and install a new pin, or you can remove the existing pin and put a tiny drop of solder at the wire/pin interface for a repair, the best repair is to order a new connector/harness end from Casper's and replace the original.
Now, I am trying to figure out how you get 7 on the maf readings. On the file that I went over and downloaded off that other site, it starts at 7.9 on the maf display but it changes to around 20 on read outs around sample #512 and stays in that range for the rest of the log other than the spikes. The file I looked at is labeled Hesitated_Park ed.
Would someone else look at that file if you bothered to dl it and tell me if you see it increase to the 20 range from the high 7's?
Necked down means like a funnel is necked down from a large opening to a small opening. That is probably Texican slang. The correct maf is straight thru with no change in internal diameter. I am not talking about the air smoothing cone in the front of the sensor which smooths air flow across the sensing board. I am referring to a reduced internal diameter as compared to the outside diameter of the unit. There were some maf sensors made for other cars that were built like this and they sometimes show up on the rebuilt market as sensors for our cars...and they are not.
Now, as Rich said above, don't waste your time trying to keep a factory style unit working in the future. Get a Translator unit along with a TT chip and eliminate the maf problem from now on. I guess there are cases of the modern style mafs failing but I have yet to see it.
30 years ago, I bought my GN and a week later I was in Columbia and my wife called and said the GN is blowing black smoke and running terribly. She took it back to the dealer and, you guessed it, the maf was bad...one week old. They have been failing regularly for 30 years now.
I hope the shop does not charge you anything.
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If this is an original maf you are wasting your time with it. There is a reason just about every turbo Buick you see that is driven has a translator and a newer style maf. The originals have lived their life cycle.
Added: After reading Steve input, I'm also willing to bet this maf doesn't make it to 255 @wot either. The translator is hard to swallow at $200 but you only have to buy it once. Worth it in aggravation. Then you use commonly available mafs you can get at a wrecking yard for a pittance. Or new or rebuilt ones for cheap compared unreliable stock ones.
Hi Texas T. I hear ya. Cut to the chase and eliminate the MAF given the ~30yrs of experience with them. Even Steve said right off the lot the MAF was bad. I've learned something and have the MAF feather in my cap :)
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the translator uses a modern maf that works differently than the original mafs. It uses the ones from modern gM engines and the Translator converts between frequency and voltage so the new ones will work on our old cars. It doesn't replace the maf - just uses a modern, much more durable one. If you don't have emissions check, you can eliminate the maf entirely but I suspect you do.
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Welcome and do you have a major headache yet!
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Mike,
I have the weatherpak tool here at the house (but, I believe you can get one from Princess Auto for a few bucks), and there is a factory MAF on the shelf. As for the MAF screen make certain it is the one into the MAF, not out of it, that you retain - reducing turbulence BEFORE the sensor wire/film is paramount to a clean signal. I also have a few GM LS1/truck-style MAFs here at the house if you go with a Translator. You can also go Speed Density as your car does not require an emissions test.
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The venturi throat (necked) MAFS are not all bad, Some work fine.