well, the hesitation problem we are addressing here is related to the p72 base ROM. Not sure how to go about your issue without seeing your maps. I mean, it may all be a tuning issue. After you completely eliminate tuning as a potential problem then delve into the other issues of a possible bug as this one turned out to be! If I could be of assistance let me know. Others here can possibly help out with tuning as well. Payne should be more than qualified to get the tuning correct.

torin

 

tom did do a complete tune both on the street and dyno.. it wasn't till after we took it on the hwy on the way home did we notice the hesitation still... so we took it back to him and his conclusion was the faulty 02 sensor

 

Yeah, what about us LS guys. Doug, now you gotta help us out!!!

 

im willing to bet that the hesitation is only on the 94 ecus... i believe they have some similarities to the p72 if im not mistaken (which i probably am) so i guess someone who is into ecus could check this out. I just like metal...

 

The P72 and P74 (94, - 95 integra LS ECUS) are similar internally. If there is a bug in the P72 ROM and we find it, it will probably apply to the P74 ECUs as well. If you have a vacuum gauge on your car, you can help us by verifying that that the hesitation occurs at a specific manifold vacuum. You may be able to run a P28 ROM in these ECUs with the VTEC point set to 8000 RPM, but we have not checked this to see if it generates a VTEC error. These ECUs do not have VTEC circuitry.

Now that we are getting some hard data on this, it should be resoved fairly quiclky.

Tuning with the knock sensor.

Serious tuners disable the knock sensor. The stock Honda knock sensor retards by up to 12 degrees under 5000 rpm, and doesn't do anything above 5000 rpm.
Forged pistons can rattle triggering a false retard and making tuning difficult. I have seen instances where knock was occurring. The tuner didn't hear it and added about 12 degrees of ignition timing to compensate. Not a good idea.

Doug

 

mine's a 1995!

 

that's weird because i have the hesitation problem with my p74/75 ecu from an obd1 ls. the problem still persists but, not to a large degree as before.

 

may be related as well. Can you describe your hesitation problem? Can you send me a copy of your ROM file to look at?

 

when i said 94, i was referring to the p75s, but thats because i felt a 95 that didnt have the hesitation... come to think of that it may have been a 92 ecu... hmm i dont remember. Either way, its p28 for me. theyre cheaper, easier to find and dont hesitate. What more do you need?

 

i can't send you the rom file because i have the 2b and someone else did the tuning for me.

but, the hesitation problem was like everyone elses. it would hesitate when it would transition from 5" to 4" of vacuum at 3000 rpm at 70 mph cruising. it was REALLY bad at first where i thought the hesitation was detonation. the tuner corrected the problem and now the hesitation isn't as violent but, it is still apparent when cruising. the hesitation occurs the most when i'm at that speed and rpm when i'm going up a hill.

 

GruvyTune how do you keep burning out your rom burner.. what causes this.. witht he emulator.. and whats the best way to avoid this.. after all i don't wanta burn outmy rom burner !

Regards James

 

Tell me what's on your car (everything). Get your tuner to send you a copy of your ROM file. Or, send me your chip and I'll make you a new one with the appropriate modifications.

 

You have to open romeditor and open a rom and download a rom to emulator all before you plug it in. That lowers the supply voltage. then you plug it in and redownload.

 

UPDATE.

I sent the files to Doug. I was able to mostly fix the hesitation on the P72 based file by smoothing the timing in an area where on the stock gsr there is pullback on the timing around 400mbar vacuum at low throttle. I'm not sure if that would help everyone since it may be a requirement with the stock manifold. However the hesitation is still there!

Hesitation is completely GONE with a file based on Hondata's base P28 OR P30 ROMs. I datalogged everything and for the life of me, can't see anything suspicious even though the hesitation is obviously felt when driving,

Anyone know anything about this EVAP solenoid thing? Mine seems to run hot all the time. Is this sensor logged in Hondalogger because I don't see anything showing up when I graph this sensor. Can anyone confirm this? I'm waiting on a reply from Doug,

Torin

 

I have a 95 ecu..havent got the hondata installed.....i know ill have the hesitation..with my luck ...
GRUVY...the reason i want to sell my hondata is..
I can sell it all and the money i make will be EQUAL to that of the aem system on the gb! SO that means for the price of a whole 2b set up(ecu, 2b etc) i can buy the aem(sell my tt and ill have EXTRA cash)
OR, i could just sell the 2b by itself and buy and get a 4b.(but I would need to purchase the pocket programmer woudl I not?) so this puts the hondata MORE expensive than the AEM(itll be easier to tune but a little more $$)
doug told me to call him. I think i may just do that.
hmmmm.


[Modified by SiRkid, 2:34 AM 6/17/2002]

 

Yes.. i will agree with Doug... we've found that on 99% of the hesitation issues (on any ECU) is the simple LACK of tuning... almost 99% of the time simply burning a stock p72 program for any motor will cause some idle and part throttle issues.. with our in car wideband, we've discovered that the majority of the time between 2500-4000rpms the p72 stock rom is WAY too lean.. (on the order of 16:1 - 17.5:1 A/F)

This is even more prevailent on overbore blocks (ie. 84-86mm bore)

I *HIGHLY* suggest that each and every one of you to PLEASE take your hondata setup to a *KNOWLEDGABLE* hondata tuner to rid your part throttle issues before jumping to conclusions.

Part throttle tuning is by far the MOST DIFFICULT part of tuning any setup. By comparison - full throttle tuning, any monkey with a wrench can do a pretty good job.

HTH

 

When I still had Hondata, the wideband datalogs showed 13:1 AFR under slight accel when the hesitation occured. Playing with the ignition timing could make the issue less apparent, but it was always still there and obvious. Always at -350 mbar @ 2900-3400 rpm.

Dustin

 

Sorry,
this problem is not strictly a tuning issue. Wideband shows stoich. and flat across my throttle ranges. As Dustin points out, timing adjustments can reduce the problem but it is still there! This is a problem with the base ROM from Hondata. I think Doug should be able to work this out. I hope so for those folks who want to still be able to use their GSR manifolds as they are meant to be used. Seems like a rather lame fix to use another ECU's base program but apparently there is not much info on these ROMS to make much difference.

 

i am so tempted to make the 5-6 hr trip to have you tune my car, i too have the hesitation. im still untuned, im just worried something might happen along the way, YOU MAKE HOUSECALLS?

 

I drove 6hrs the first time I TRIED to get my car tuned.
You may be alright getting it here on a basemap. Or just drive it over with your stock injectors and stock ecu and we install the rest here. But, I'm sure we can provide a good basemap to make the drive without it causing any harm whatsoever as long as you aren't making crazy boost.

 

Hah!
I took off my Unorthodox Pulley and replaced the stock one and would you believe the timing on my car had been retarded to like 12degrees BTDC based on the mark on the lightened pulley!

Now i'm back to stock and i get even better power, no wonder!

 

well at the moment i no longer have my stock injectors or ecu, its already running on 440cc injectors w/ a base map sgt provided. runs ok now, just dont know how well it run once boosted. im just worried of something popping loose or something, guess i gotta make sure everything is 100% legit before i take any long trips.