get a new alternator those things suck so bad check your battery too the alternator probably killed that also. if your secondaries weren't working then you wouldn't be able to drive past 3800 the hesitation is a grounding issue or probably because your alternator is working right. also has your injectors ever been cleaned? my old turboII had tons of hesitation isuues until i got the injectors cleaned.

i have a few fd alternators laying around not sure if they work or not.

yeah, getting a new alternator soon > looking into an FD swap?? How does that work because it looks like it uses a different belt then the S4?

The battery seems just fine, it's holding power and cranks the car up perfect each time.

I am able to slug myself beyond 3800 rpm...it's significantly slower then it should be, you can feel the primaries cutting back. I don't think my injectors are clogged considering they work intermittently and when they work, THEY WORK. The car will pull hard and fast all the way to the redline...sits you back in the seat. When they don't work, you can floor the pedal, sit back in the seat, and when you hit 3800 rpm you actually get shoved forward a little and it's a super slow climb from there. As for the cleanliness too, we ran a very rich mixture of injector cleaner in the tank about 4 times, and like I said, when they do come on, they are strong.

I'm really thinking a huge problem is with the alternator. You mentioned "i have a few fd alternators laying around not sure if they work or not." I would ask if you could have them tested and maybe let me buy one off you and mail it, but I don't think I would save anything since I live in Georgia and would have to pay shipping.

Thanks.

You need to check the Pressure sensor as it's job is to sense load on the engine which then allows the secondary injectors to work. W/o load the secondary injectors won't fire. There is an easy way to see if the Pressure sensor is a contributing factor. Disconnect the vacuum hose to it and cap the hose. Then disconnect the plug to the TPS. Doing so simulates load and will bypass the sensor. Take the car for a ride. Also, it's not really wise to drive the car with an alternator that is operating in a manner such as yours.

Totally! I'm not driving it unless I ABSOLUTELY have to. I don't want it to seize up and cause more problems (especially getting stranded).

This did not solve the problem. Last time I drove the car, the injectors were not working. I went out and performed these steps and drove the car cold up the driveway and down the road. The injectors were working. I pulled over, reconnected everything, and almost immediately they stopped working...I thought problem solved. But to be sure, I disconnected again and plugged the hose, but they still were not working.

Not sure if there is a correlation, but it seems pretty consistent that I'll drive the car home with them not working, but when I get in the car cold and drive off they are working, but somewhere in there when the car warms up they stop working. At the same time though, they have worked TONS of times with the car warm. I think this might just be coincidence since my driveway is very bumpy (I try to go up and down it as smooth as possible but it's a gravel hill). There have also been times I've driven the car to my parent's house in a neighborhood and parked in the road. When I left, the engine was still warm and the injectors would fire.

But it just seems weird that every time I pull out of my driveway cold, they work. (additional note here...until they started working for the first time after I peeled out of the gas station...this was not the case - they didn't work period. My guess is the ECU ground fix has influenced them working half of the time)

*Anyway, the summery is the pressure sensor is not the cause for my problem. Any other easy sensor checks?

Oh yeah, another observation which takes me back to the alternator. When I first started the car to do the test the gauge was reading 14v. Same as when I drove it down the road and stopped. It remained at 14v. However, when I plugged everything back up and everything at warmed up, the alternator started acting up and the gauge was reading low and almost at 12v when I was sitting at idle. After about a few minutes the alternator gets really hot and I'm noticing that's when it starts reading various volts.

Yep, alternator's crapping out.

https://www.rx7club.com/showthread.p...ght=alternator

I have a pulley made for an FD alt on an FC. If you need it, let me know.

Standalone ecu: Not a factory computer that you can tune the car with using a laptop or palm pilot. Usually, you get a whole new wiring harness, and all new sensors. Good thing about them is that they're usually MAP based, so no MAF sensor. I have a megasquirt ecu, and it only uses 6 sensors, most of which have been replaced for GM units. They're weather sealed, cheap to replace, and easy to find.

wayy to much to go through and cost. I don't think this is a mod I need to worry about doing considering the car is stock and for the most part will remain stock. I have no need for heavy modding like this. Everything in the car worked perfect before it sat for a year and a half so all I need to do is find out what deteriorated in that time.

As for the pulley..how much you want for it? Is it the proper size for the job (meaning it's not going to cause under-drive or other problems like I've been reading researching this swap)?

You wouldn't happen to have an FD alt too that works would you? haha :lol:

Ok....new alternator. Had to go stock S4 since I really needed to get one asap and I don't have a plug for S5 or FD plug or pulley for FD and no time to wait for one since I needed to get my car on the road again.

Swapped the alt and put a new battery in. Not happy with the alternator but at least it's not seizing up and shredding belts.

Since the swap, my injector system has been on the fritz. I still have the same going on with my secondaries. They always work when I start the car cold but something happens after it warms up to make them stop working (or at least work properly). What I get is a serious power cutback at 3800 and it just slowly climbs and accelerates after that. Now, since the new alt, if I turn all accessories off then I will notice them trying to work. What I mean is I get a hair of a second jump and it falls back again.

On top of that I am now having my primaries giving me trouble. I'll start to accelerate and it seems like I nearly get a complete fuel cutoff for a second and it comes back on. It happens very randomly and intermittently. It's not every time the car gets driven or made to accelerate and it's not even under heavy pedal every time it does it. It only started doing this after I put a new alt and battery in the car.

The only things I noticed during the swap are bad wires going to the voltage regulator plug on the alt and the clip broke to the back of the housing for the water pump/thermostat/temperature sensor (not sure exactly what it is there sorry). It's the clip that is similar to the ones for the injectors located right under the alternator. It's held on securely right now but it's not perfect...just enough to keep contact.

At this point would my problem most likely be with the ECU? I can't explain this kind of intermittence with anything else. They work and don't work properly so randomly after the car gets warmed up. I am only trying to find this stuff out so I know what I can part of on this car without selling bad parts. I am buying an S5 to swap my motor into and hoping I'm good. I expect some things to work on, but at least I'll have a good body and a lot of other good things going for me that I don't have now.

The sensor on the back of the water pump is the Water Thermosensor and it is one of the more important sensors on the car regarding driveability so you need to fix that problem.

Understandably so and I'm on that asap. But I'm sure it's not affecting the issues I'm having so I'm just aggravated. Where do I find this style clip? I have been looking around and so far no luck. Would be nice if the engine harness is in good shape that I can part it out to someone who needs it.

Search and you shall find.


https://www.rx7club.com/showthread.p...rmosensor+plug

thanks satch

is it a common thing on a 88 vert that has a s5 engine for the gauge cluster to just stop workin checked fuse it was blow put new one in and instantly blew again anyone else experience this?? is there a problem area that is known for a short to happen?

What sucks is likely you have wires that are exposed somewhere under the dash that is touching something and grounding it out. Or another strong possibility is a bad clip/harness somewhere in there that is allowing contact between wires. I say it's highly likely you are looking at removing the dash to check all the wires in the bundle. I would start first with the cluster panel. Remove it first and check everything. Next you can pull the carpet away where your feet go on the passenger side and take a look at what you can see from there. If not those places, then the rest of the dash so you can assess the rest of the bundle.

Those are just my thoughts...

The Meter fuse, which powers the gauge cluster also provides voltage to many other items. Use the advanced search function and type in meter fuse and then select "2nd generation specific" from the forum list to search in followed by "search now" at the bottom of the screen and you will find all the necessary info to start your search for the cause of your issue. Many times the reverse light switch located underneath the car is the cause, primarily because the wires are exposed to outside factors.

Thank you guys I really appreciate it

**UPDATE**

^Quote: "On top of that I am now having my primaries giving me trouble. I'll start to accelerate and it seems like I nearly get a complete fuel cutoff for a second and it comes back on. It happens very randomly and intermittently. It's not every time the car gets driven or made to accelerate and it's not even under heavy pedal every time it does it. It only started doing this after I put a new alt and battery in the car. "

This was fixed when I did a simple jimmy rig fix on the plug for the water thermo sensor by gluing it in place with blue lock tight on what was left of the plug and wrapping it with tape...held really good.

The problem with my hesitation continued to get worse and as it did, it started to seem like it was 100% dependent on temperature. It always worked and pulled HARD when the engine was cold. However, it would hesitate once it got up to operating temp. Instead of the nice hard pull it would cut way back, still accelerate, but very slowly.

I figured with this having started and being completely repetitive I figured water thermo sensor must be bad. Since I would have to take it out in order to test it and one from Advance Auto was only $18, I figured I would just go ahead and replace it since it was old. I also replaced the clip with a spliced in injector pigtail.

While I was there and had to remove the alternator anyway...I had an FD alt I bought to put in my S5 because it's alternator is fried. I set it in and just used a couple of wires I spliced some male and female connectors on each end to connect from the stock pigtail to the FD alt and fitted the B-pole wire to it without splicing it to fit properly. Yes I know this won't last long, but I wanted to see where I would go with it.

After the fix, my hesitation problem is GONE most likely because the sensor. Also I am now able to play a CD without the power cutting out every time I stop and have the breaks pressed. Just replacing it with a stock alt it kept the radio from dying out but a CD would cause it to cut out even while cruising at 55. I don't think I got a quality S4 alt from the store and may see about returning it.

Anyway, it seems everything is now running 100% so for now I'm okay! :D

Ok. Drove the car a bunch having fun with it running like a champ....all great things come to an end and I'm officially irritated beyond recognition!

The hesitation is back and is right back to where it was before I replaced the sensor and alternator. It does not look like any of the work I did has come apart.

It runs great. When cold it pulls hard and fast but as soon as it warms completely to operating temperature it hesitates at about 3800 and very slowly climbs. The [I]slowly[I] stressed meaning it is so slow and drags that when I press the clutch the car actually speeds up momentarily. It's not acting like a rev limiter when it happens because I am able to continue to speed up and the rmp's still rise...just incredibly slow and only when the engine has fully warmed up.

I am at a loss on this issue as I have done work that would temporarily fix it without knowing what fixed it. Then it would stop working again and now it's created this clear repeatable behavior so I replaced the sensor. That worked immediately and the car gathered at least 150 miles of "full operating temperature" miles without a hick-up. Now...well, you get it...

Am I back to the wiring harness?...nothing seems bad for what I can see without taking the thing apart. :scratch:

i tell all rx owners to add extra grounds... it wont hurt anything. I add 8 guage amp wiring wire with soldered on ringlugs. and makesure the mounting area is good and clean. I ad wires in this location. battery-body, motor to strut on each side. alt to motor, 4 from ecu to body.
I steped up the alt on my 89 to a jdm 20b alt. 120 amps i think

Not to be rude...but if you had read the previous posts in this thread you would see the car has already had all of this done to it already. It has all those grounds added to it that you listed plus a few more and I've also added an FD alt with 110 amps.

I am pretty sure it's a worn wire somewhere, most likely under the UIM that is intermittently shorting out on the motor or the like. Everything I have done is coming back to that conclusion. I do work, it fixes it for an amount of time then it acts up again. I took it out today and it even hesitated when the engine was cold but it was acting just like a vibrating wire that was touching and not. It would hesitate, but to different degrees and it would even slightly boost a little while it was hesitating like the wire was coming off the short and it would try to work for just a hair of a second or it was just barely touching what it's shorting on.

Everything else, sensors, etc. has been ruled out. When it works, it works awesome and last I was under the hood it worked for a clear 2 weeks before not working again. However, I am putting this problem aside because come spring time I am swapping this motor into an S5 with a blown motor and I will take a look at all the wiring when it's out. I see no reason to worry about taking it apart when the car is perfectly drivable as it is....irritating as the problem is...

if anyone disagrees with me you are welcome to share your thoughts but I've done a lot and I keep coming back to "I've wiggled a wire away from a short and it's worked it's way back."