DavidHolmesIII

Thanks for your time, have the 3800 hesitation and am curious if the problem is more likely the grounds VS the ecu. I have read that it can be caused by either one, but both areas claimed to be the problem 90% of the time. My ecu is indeed in need of replacement, horn problems...etc. Do you think that i will have the problem post ecu replacement?

88 GXL NA

texFCturboII

iTrader: (17)

The ECU doesn't control the horn, first off. BUT the easiest way to fix this is to go ahead and jumper a ground off the ECU to the body from the actual ECu ground.... make sense? This will tell you if your hesitation was indeed caused by the grounds or:

1) secondary injectors
2) TPS
3) a couple other reasons.... and finally
4) the ECU

DavidHolmesIII

Thanks for the information. You should probably up the condesending aspects of your personality.

Ex-Eg-Driver

iTrader: (1)

AUGieDogie

iTrader: (4)

the CPU is most likely your horns problem. Its under the left dash.

the hesitation is a PITA some people cure it with the pressure reground some don't. Some get it with the ECU ground some don't. Go through and try them all and sometimes you get it sometimes you don't. Sorry i can't be more help but the hesitation can be a bitch to track down.

DavidHolmesIII

Thanks augiedogie. good to see that not everyone who knows about these cars is a *****....thanks again

texFCturboII

iTrader: (17)

Didn't realize I was being a *****... my bad. If the hesitation is exclusive to 3500 - 3800 rpm's then it is most likely a grounding issue. Follow AUG's advice and check out all your grounds, look for Superground somewhere, I hear a lot of poeple having success with that. For me, my hesitation wasn't exclusive to 3500=3800 rpms and it turned out to be my TPS.

schctrg

wow i didn't think it was condesending .. i thought it was nice and he just wanted to make sure it made sense, but who knows i could be wrong =O

DavidHolmesIII

Yeah its exclusive to the 3500-3800 range, however it doesnt always do it. I will check the grounds. Would'nt be shocked if the TPS is bad. One question... the jump ground, is that just an additional ground spliced into the existing ground? Forgive me for the lack of knowledge on my vehicle, I am only 23 and have only a novice skill level when it comes to electrical anything.

Perhaps you were not being condesending, quite difficult to judge tone while reading. I get the "damn newbie" mentality with a lot of the responses here. I try and read the faqs and not ask obvious questions, but obviously I am new at this.

texFCturboII

iTrader: (17)

That's basically it, I tried to find a link to show some pictures and step by step directions, but I'm internet-retarded sometimes. Basically you pull up the carpet on the passenger side, and there is your ECU. It's got some metal around it protecting it that you will need to remove to access it. Grab an FSM and find which wire is going to be your ground. (there are a lot, and this is where the pics would be helpful, someone help me out...) take some 18 guage wire and splice it into the ground using a good solder and heat shrink. It may take a couple tries to get the wire to take the solder, I'd practice if you haven't done anything like this before. Then getchya a ring connector and attach it to the other end of the jumper wire and bolt that to a nice clean piece of metal on the car (one of the bolts holding the shield is ideal!) bam there ya go. Also, check this out:

http://www.aaroncake.net/RX-7/grounding.htm

That's got some good tips and also tells you about an additional boost sensor ground that may help too! A great site to learn from as well: 1300cc.com and rotorwiki.com plenty of info out there for these cars. Enjoy and good luck!

DavidHolmesIII

My main concern at this point is the emissions. Tired of getting pulled over for expired tags. I hope to check back with you on this after I can finish the emissions issues. Thanks again.

Nate83RX7

If the Ground and the TPS arent the cause of the problem wat could be?!!

texFCturboII

iTrader: (17)

secondary injectors, ECU

ericgrau

iTrader: (1)

The 3800 rpm hesitation is caused by the failure of the secondary fuel injectors to kick in quickly enough when needed. All of the above mentioned causes are related to triggering the secondary injectors. So if none of those fix it, that'll at least give you an idea of what other components might be related. But I think it's usually the ECU ground (i.e., the ECU works but it's sending a weak signal to the secondary injectors). Mazda introduced secondary injectors that kick in only when needed to improv fuel economy.

DavidHolmesIII

Mine tends to flood about 1/30 starts...could that have anything to do with the secondary injectors?

Toxindude

I had 3800 hes problems a while back . One thing I never see mentioned in the forums and I am not saying its not out there somwhere . Is the Fuel Injector resistor pack . Test it for continutity if you don't know where it is its located underneath where the air filter box would be attached to the right wheel well . That was what was wrong with my car . I figured that out after regrounding everything under the hood and the ECU . Have fun

Icemark

Probably low compression, or loose nut behind the wheel (don't give it any gas when starting- don't even touch the accell pedal when starting) if flooding is that random.

actually around 3800 the 2ndaries kick in to change the placement of fuel in relation to the intake path for more power at higher RPMs, not for fuel economy.

when the 2ndaries kick in, the primary's dial back by 50%

DavidHolmesIII

I noticed the last 2 times it had flooded i had not fully let it warm up before i cut it off, like a gas station run. Someone told me that might have something to do with it, had compression checked about 6 months ago and everything was just about perfect. S4 13b NA , it was new about 30,000 miles ago. I never give it gas while starting....

Icemark

what do you consider "just about perfect"?

Flooding when you didn't warm the engine all the way is a typical rotary issue, but much more common on a lower compression motor.

DavidHolmesIII

Around 85-90 psi. Rear rotor is slightly better. Good Even bounces. Sorry Icemark, if I had noticed it was you I would have been more specific.

Icemark

wow, that low?.. that would be far from perfect and what I would consider a candidate for rebuilding.

Perfect would be 125 psi... even the factory suggests rebuilding at 85 PSI.

NZConvertible

The staged injection was introduced to allow more precise fuel delivery at low load while still providing sufficient fuel at high load. It's much easier to provide accurate fuelling with a small injector than a large one, and that improves idle quality, emissions and to a small extent, fuel economy.

nvrdone

I fixed my hesitation problem by replacing my fuel filter.

DavidHolmesIII

Well, I knew that I shouldnt have expected much from my local master tech, at least as far as my rotary car goes. Do you think that a street port would interfere with the emissions?... Im riding a very fine line as of now, and antique registration isnt an option until 2013. By the way, Aarons re-grounding write up was sufficent, hesitation is gone!