Experience with "DiabloSport Tuners"

[4 the ride]

Just a thought, After doing a series of High RPM engine pulls on the dyno, perhaps you have actually fouled the MAF. Easy things first, try cleaning it with MAF cleaner and make sure your new Green Filter is not over oiled. I have yet to have this problem on my Vette but I've had it numerous times on my Silferado. A good MAF cleaning solved the problem every time. I would usually get the fault a week or so after cleaning the K&N filter and re-oiling it.

Thanks, I too thought of this and will try. VaraRam swears that the oil on the Green Filters won't do this but who knows. I didn't look to be over oiled but this is the route we will take first. After about a half dozen pulls on the dyno it's entirely possible.

 

[Hib Halverson]

Ok Hib, and others who responded to my "DiabloSport" post last week.

JUST WENT OUT AND READ THE CODES - They're different codes! Maybe another problem as a result of the tuning. New codes are as follows: 1 of 2 - P0101 Vaf Ckt Range/Perf and 2 of 2 - Maf or Vaf Ckt Range/Perf.

Ok, so for now, the system is not lean, or....it's not so lean as to set a fault code. From what you say in the post before the above, about the guy in Traverse, it sounds like the system is still lean at part throttle and that's what sets lean exhaust codes, once the system is adding all the fuel its LTFT range allows.

DTC P0101 is a fault code for the MAF. The Service Manual discussion of this is rather lengthy but in short, 0101 will set if the MAF sensor sends data that doesn't agree with the predicted airflow as suggested by the ECM's MAP, IAT, ECT and RPM inputs. Keep in mind that the range of expected MAF signals is, to a certain extent, governed by how the ECM and the MAF are calibrated.

This code may set of the MAF is faulty due to contamination (oil, dirt, scummy stuff...whatever). It also can set if there's an air leak between the MAF and the engine. It can set because of various electrical issues. It can set if there has been water intrusion or ingestion. It can set if the throttle body is gummed-up. It can set due to RFI. It can set if the induction system is restricted. It can set of air flow though the MAF is greatly enhanced over stock and the calibration is not correct at part throttle and below 4000 rpm.

What I'd do is connect a scan tester and get the failure records and not them. Then clear codes and road test. If the code resets and there are none of the diagnostic issues per the FSM in re: P0101 other than the aftermarket intake system present, then I'd take it back to the dyno service and ask them to tune the part throttle such that the LTFTs are a little closer to zero.

I'll add that with my 04 Z06, I had this code set one time after I reverted to the stock MAF and filter assy after using a aftermarket MAF and filter assy. Originally, I had calibrated for the GMS parts but when I went back to stock, I got a P0101 along with the two lean exhaust codes P0174, 0175. I recal'ed the part throttle, again, and so far no codes.

As I said earlier, this engine controls cal s&%t ain't easy.

Lastly, with all due respect to my drinking buddy, Catbert, "EFI Live" is not obscure tuning software. While it is true the people who publish the software are in Australia and that HP Tuners has received a lot of attention, there are a number of tuners who use EFI Live. Currently I use HPT but I've been thinking about trying EFI Live just so I can become familiar with it.

 

[4 the ride]

Cleaned the maf sensor

Thanks again Hib. I just cleaned the MAF sensor with MAF cleaner and checked the codes again. Now, bear in mind that I had shut it off and restarted once since my last post on the codes indicated. Once I cleaned and reinstalled the MAF I plugged in the OBD2 Scanner and it only showed one code "P0101 - MAF or VAF CKT Range/Perf. Don't know what happened to the other one but this is all that displayed. Also, I noted no visible film or deposits anywhere on the MAF or in the air passages. No more driving today but will take it out again tomorrow.

On a related point, if in fact a contaminated MAF does turn out to be the problem, how might this impact my dyno tune? I'm thinking that you are right, he needs to richen up the LT-MT range and this should handle it.

 

[Hib Halverson]

Thanks again Hib. I just cleaned the MAF sensor with MAF cleaner and checked the codes again. Now, bear in mind that I had shut it off and restarted once since my last post on the codes indicated. Once I cleaned and reinstalled the MAF I plugged in the OBD2 Scanner and it only showed one code "P0101 - MAF or VAF CKT Range/Perf. Don't know what happened to the other one but this is all that displayed. Also, I noted no visible film or deposits anywhere on the MAF or in the air passages. No more driving today but will take it out again tomorrow.

On a related point, if in fact a contaminated MAF does turn out to be the problem, how might this impact my dyno tune? I'm thinking that you are right, he needs to richen up the LT-MT range and this should handle it.

I just want to make sure I read the above right...

You cleaned the MAF, reinstalled it and immediately saw that code, again?

After you cleaned the MAF but before you started the engine, did you clear codes?

Also, I just remembered, the 02-04 Z06es had a special MAF with no flow-straightener. Does the VaraRam you have use a straight duct between the filter assy and the MAF or is the duct curved or has a bend in it?

 

[4 the ride]

I just want to make sure I read the above right...

You cleaned the MAF, reinstalled it and immediately saw that code, again?

After you cleaned the MAF but before you started the engine, did you clear codes?

Also, I just remembered, the 02-04 Z06es had a special MAF with no flow-straightener. Does the VaraRam you have use a straight duct between the filter assy and the MAF or is the duct curved or has a bend in it?

I saw the check engine light on the way home from running an errand, pulled in the drive and shut it off. Latter, I pulled the codes and found the two referenced earlier P0101 VAF CKT Range/Perf and P0101 MAF or VAF Range/Perf. Latter I pulled it in the garage and shut it down. Ran to the auto parts store, came home with the cleaner, took it off and cleaned it, replaced it and BEFORE I STARTED IT, read out the codes and there was only the second one, see above, there. I then cleared them in anticipation of some road time tomorrow.

The VaraRam ducts directly into the MAF sensor, about two inches away from it. It's all in a straight line to the throttle body. This is a car with only 16,000 miles on it, everything is very clean.

 

[Hib Halverson]

Post what happens after your next road test.

 

[DrNavyRet]

I don't mean to hijack this thread, but I am curious as to why someone would buy a Diablo Predator when they are "old tech" according to Diablo web site as it is replaced by the Diablo InTune (I1000). The web site is selling out the Predator for 309 but you need to add the interface for 49.99 or 359 bucks. The Diablo InTune costs 399 and comes with the interface. So for 40 more dollars, you have a tuner that does more and is applicable to many more vehicles than the old Predator. Then I see a vendor selling the Predator for 369 and then you add the interface as well as the new Diablo Trinity; no mention of the I1000. Can anyone shed some info or knwledge regarding these units? It's like everyone is confused, including me and including vendors???

 

[4 the ride]

I don't mean to hijack this thread, but I am curious as to why someone would buy a Diablo Predator when they are "old tech" according to Diablo web site as it is replaced by the Diablo InTune (I1000). The web site is selling out the Predator for 309 but you need to add the interface for 49.99 or 359 bucks. The Diablo InTune costs 399 and comes with the interface. So for 40 more dollars, you have a tuner that does more and is applicable to many more vehicles than the old Predator. Then I see a vendor selling the Predator for 369 and then you add the interface as well as the new Diablo Trinity; no mention of the I1000. Can anyone shed some info or knwledge regarding these units? It's like everyone is confused, including me and including vendors???

THANKS, Yeah, I caught this, in fact the sales guy at DiabloSport dissuaded me from buying a Predator and turned me on to the "InTune" and Diablew, who is one of their preferred vendors. Turns out, I won't be buying one after all, at least not now.

Regards

 

[4 the ride]

No new codes:

Post what happens after your next road test.

Hib,

I took it out today and drove about 25 miles. Ran it up to 6000 rpm in second and third, nothing happened and it seems strong. So, did my MAF cleaning work? I don't know yet but if the check engine light doesn't come back next week when I will be driving it more, we may know the reason. I did notice a slight bucking around 1500 - 2000rpm as I backed off the throttle but very light. May mean that the light will come back as I drive it more. I will revert next week. Oh, BTW, it was in the 80's here today and this may have helped keep it from tripping over the line.

Regards,

 

[4 the ride]

The latest on my tuning debacle

Wow! And the mechanic that checked it out couldn't find anything and wanted to blame it on oil from the new "Green" filter. I can say that the car has run perfect since I got it until I changed the filter, or something else went bad and we aren't seeing it. I will let you know how I come out. Thanks for taking the time to help me.

Jim

Hib, et.al., So I spent the day at the tuner last week and on the way home "check engine." New codes associated with MAF this time. Took the MAF off and cleaned it with MAF cleaner, no signs of oil or residue. Drove it in warm temps. for 25 miles, no codes. Ran it up in second and third, no codes. Put it in the garage for the weekend and drove it out this morning in cool temps, low 50's. Boom! check engine! Pulled the codes, 5 of them 1. P0101 - MAF or VAF CKT Range/Perf. 2. P0171 System too lean (bank 1) 3. P0101 - MAF or VAF...... 4. P0171 - System too lean (bank 1). 5. P0174 - System too lean (bank 2). Back to the tuner in the morning for some additional tweaks but I'm loosing confidence in this solution track. I'm learning that it's not just the guy who has fundamental knowledge of tuning and a dyno but you really need someone who has specific experience with the LS engine, LS6 if possible. Oh well, at this point I'm less concerned with the ultimate tune than one that will get the LT calibrations correct. The fellow I'm using is feeling his way along with my car and I'm loosing my patients with this track. I need a pro to help him nail this tune.

Any comments?

For the ride

 

[catbert]

I'd call Chuck at Corvettes of Westchester, and describe the problem. He'll be able to tell you if it's something that can be fixed by a tune, mail order or dyno. I've never run across a tuning issue he hasn't seen a hundred times. It's worth a phone call.

 

[Hib Halverson]

Hib, et.al., So I spent the day at the tuner last week and on the way home "check engine." New codes associated with MAF this time. Took the MAF off and cleaned it with MAF cleaner, no signs of oil or residue. Drove it in warm temps. for 25 miles, no codes. Ran it up in second and third, no codes. Put it in the garage for the weekend and drove it out this morning in cool temps, low 50's. Boom! check engine! Pulled the codes, 5 of them 1. P0101 - MAF or VAF CKT Range/Perf. 2. P0171 System too lean (bank 1) 3. P0101 - MAF or VAF...... 4. P0171 - System too lean (bank 1). 5. P0174 - System too lean (bank 2). Back to the tuner in the morning for some additional tweaks but I'm loosing confidence in this solution track. I'm learning that it's not just the guy who has fundamental knowledge of tuning and a dyno but you really need someone who has specific experience with the LS engine, LS6 if possible. Oh well, at this point I'm less concerned with the ultimate tune than one that will get the LT calibrations correct. The fellow I'm using is feeling his way along with my car and I'm loosing my patients with this track. I need a pro to help him nail this tune.

Any comments?

For the ride

You really only have three codes, 0101, 0171 and 0174. Two of them may be both history and current so they show-up twice.

First thing I'll say is: I wish I could see the failure records for those DTCs, but without a real scan tester, that info is not available. It would be interesting to see what conditions are present when the faults occur.

Secondly, there's not been much progress, in spite of your tuning sessions, because you still have the same problems. I think I've said this before, but if I haven't....the faults are likely connected with part throttle operation not high load or WOT.

Third, your problems are not specific to the LS6 engine or even Gen 3 V8s in general. Modifications which change the way the engine controls work at part throttle can happen with any engine.

The tuner who solves this problem will:
1) ...address why the MAF sensor is sensing airflow rates which do not match the expected rates computed by the ECM
2) ...if necessary, retune the engine's part throttle fuel delivery such that the system doesn't "hit" the long term fuel trim limit.

To be honest, if it were me, at this point I'd be thinking: You know, I've screwed with this VaraRam long enough and it still causes my engine controls to set codes. Time to return it and ask for my money back then go looking for something else.

A question which may not have been asked before: do you have the 2004 Factory Service Manual and have you read the diagnostic info for those three codes?

Lastly, with respect to the MAF code, while it is true a whole host of problems (contaminated sensor wires, air leaks downstream, bad connections, dirty throttle plate, water intrusion, etc,) can cause DTC P0101 to set, because these problems began with a change in the air filter assembly ahead of the MAF, close attention should be paid to the following paragraph in the FSM

Conditions for Setting the DTC
The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4 seconds.

Continued, good luck.

 

[4 the ride]

You really only have three codes, 0101, 0171 and 0174. Two of them may be both history and current so they show-up twice.

First thing I'll say is: I wish I could see the failure records for those DTCs, but without a real scan tester, that info is not available. It would be interesting to see what conditions are present when the faults occur.

Secondly, there's not been much progress, in spite of your tuning sessions, because you still have the same problems. I think I've said this before, but if I haven't....the faults are likely connected with part throttle operation not high load or WOT.

Third, your problems are not specific to the LS6 engine or even Gen 3 V8s in general. Modifications which change the way the engine controls work at part throttle can happen with any engine.

The tuner who solves this problem will:
1) ...address why the MAF sensor is sensing airflow rates which do not match the expected rates computed by the ECM

2) ...if necessary, retune the engine's part throttle fuel delivery such that the system doesn't "hit" the long term fuel trim limit.

To be honest, if it were me, at this point I'd be thinking: You know, I've screwed with this VaraRam long enough and it still causes my engine controls to set codes. Time to return it and ask for my money back then go looking for something else.

A question which may not have been asked before: do you have the 2004 Factory Service Manual and have you read the diagnostic info for those three codes?

Lastly, with respect to the MAF code, while it is true a whole host of problems (contaminated sensor wires, air leaks downstream, bad connections, dirty throttle plate, water intrusion, etc,) can cause DTC P0101 to set, because these problems began with a change in the air filter assembly ahead of the MAF, close attention should be paid to the following paragraph in the FSM

Conditions for Setting the DTC
The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4 seconds.

Continued, good luck.

THANKS;

I agree with the above, your thinking is right on and in line with my tuner. The VaraRam seems to be the culprit in that it all started with the filter change. I was going to remove it while in Fla. but didn't have the facilities to get the car up in the air, nor did I have my tools so did the filter upgrade.

I just returned from the tuner, he's a good guy and continues to try hard but I'm afraid the learning curve is too long for my attention span. At any rate, we spent three hours tuning with EFILive only, no dyno, and found that if we left everything over 2,000 rpm alone and concentrated on 800 - 2000 and added fuel here it may work out. I'll spare you the hiccups but in the end it seemed to work. We agreed that I would drive it for the next week and see how it goes and then put it back on the dyno. I just may end up down state at a tuner with demonstrated experience in cars like mine. More latter.

Thanks again
4-The-Ride