so yeah thats about it....i just recently installed 720's and rtek 1.7 and i am still getting a really bad hesitation at 3.5 k if i DONT BOOST. if i boost at all its just like it was never there. i find this weird because i had checked all the ground connectiongs before. before i had installed these mods i diddnt have the hesitation....

my power mods also include: RB full racing exaust with no cat, s- tune intake, 10mm wires, FD fuel pump, apexi safc 1, lm1 wideband, 720's and rtek 1.7.

any help would be great

 

THis is the most common symptom of a bad grounding system. If anything, I would think its your pressure sensor that is not correctly grounded. There is an absolutley wicked grounding guide in the second gen archive, I followed it to the letter and my electrical system is very solid.

 

yeah i also hear the most common is the pressure sensor also...ill give it a try
thanks

 

Do not reground the PS if you do not have a 86 rx7! You wil burn your ECU up.

If I am correct later models use a ground from the ECU. But all the other grounds go for it :-) Sounds like the ground on the harness under the UIM attached to the rear rotor housing. Visit the FAQfor icemarks report on hesitation and the archive as stated.

 

bu tas he pointed out "BOOST" he has a t2

 

Whats the basis for NOT regrounding the Pressure Sender? Explain your position on this please..

 

I have an 87TII and I have been having a similar problem since I installed the my Rtek. I have added and refreshed grounds as per the Kevin Landers right up. My TPS is adjusted correctly and only 1 month old. My 720s and 550s were all cleaned prior to going back in. I changed a thermosensor on a hunch but no change. I checked codes and I have none. I can get rid of the hesitation by turning the car off and on. But it comes back after a few minutes. I am beginning to suspect the Rtek itself. I have a spare ECU and I may just try it to see what happens but this is the most frustrating problem. This mod was supposed to be plug and play.

 

I had a wicked hesitation , If you ease in to it can you tach ? I simple remvoved every electrical connector cleaned them and all was well , be sure to do the one going to the tranny.

 

IceMark stated this in the FAQ. And well a long thread with Wayne88N/A and HAILERS and IceMark that we were posting in with someone ells that regrounded there car and got mad issues. Grounded the PS above a 86 was one of the major issues that had developed in the thread.

From the FAQ
The NFO of that it will burn out your ECU was brought up from HAILERS.

 

Interesting.. when I had a pressure sensor on my 88, it was grounded. As per the Factory Recall.

 

i have the same hesitation and a r-tek 1.7 . if you read up on the chip they moved the point in the maps where the secondaries kick in .. instead of 3800 (stock) they changed it to 3500 (rtek) now only today ii have had a little chance to play around with this but i found that if i lean out the 3400k with the safc the hesitation seems to go away for the most part. and most of the time it sweeps through that rpm range fairly smooth. i think i knocked it down about 3-4 parts . i will say this im not 100 percent sure this is the cause nor did i used a wideband. but i only leaned it out a tad cuz im not pushing the car right now nor am i racing. this is just a temp fix. i can let you know what i find in a few weeks when the car gets tuned with a wideband

 

Even more interesting. This recal. Do you minde posting it somewhere or pm? I am curious what it says and why.

 

It wasnt a recall, it was a TSB, and since I am not going to shell out $24 to Alldata to retrieve their list of TSBs, I cant substantiate that claim.

However there are numerous people that I know that have regrounded the sensor at the passenger shock tower with no problem.

My guess is, the people that burned out thier ECUs grounded the wrong wire.

 

Did a search on the 3800 RPM hesitation. Lots of the aforementioned people were advocating grounding the sensor up until just recently (did I miss the memo?). And here is a guy that fixed his 87 by regrounding the Pressure Sensor.


https://www.rx7club.com/showthread.p...RPM+Hesitation

 

Here's the gist of it, Rat...

On all of the production cars proir to Nov '86, the AFM had a bad ground splice in the harness (or somewhere, anyway). The "fix" was to ground that boost sensor wire, because it was the easiest component to reach for the repair...

Gotta remember, all of the 5 volt sensors share the same ground (that way every input is on the same ground potential, makes for a more accurate mapping once the ECU plots the inputs). This ground usually terminates at that rear rotor housing ground.

Because of the Mazda snafus, the TSB bypassed this ground on the early cars and sent it straight to the chassis. I guess this seems to have worked, BUT...

Now when the car's running, instead of the sensors' (ECU) ground being near the alt (where it should be), it's on the chassis, which makes for a longer current path. And it means that your engine-to-chassis bonding better be premo...

The result of all of this rambling- some guys have followed that "grounding how to" for post Nov '86 cars and discovered that their cars are running like crap now. The reason is that their stock grounds are in good shape (rear rotor housing, specifically), and now the sensors have 2 grounds (with different potentials), which confuses the **** out of the ECU trying to plot miniscule voltages.

I've gotten more than one PM from guys that did that grounding mod and needed help in fixing their cars. This is the main reason I tell everyone to fix their OEM grounds and quit adding new ones...

As far as burning their ECUs, I have no data on that one...

 

i think its 3300 not 3500

 

So I take it you're not a fan of the Circle Earth?

 

no wayne doesn't agree with adding grounds Just to backup J-Rat in this one, I regrounded my boost sensor when I was having the 3800rpm hessitation and still have it on there now with no ill effects. The solution to my hessitation problems was either getting rid of all emissions or recrimping new water thermo sensor connectors on.