Thanks for comming this far I hope someone can help me with my problem.

Let me start with my setup.

13b-rew with a quite large bridge port, with a Garrett T04Z 1.32.
Autronic SM4, Autronic 500R CDI, Crane Cams LX92 coils. Taylor 10.8mm pro wires. tried alot of diffrent plugs. 4xbosch 1680cc injectors. Aeromotive Eliminator fuel pump and Aeromotive FPR. And running on E85

Now to the problem.

The car has been tuned on the dyno and prodused 497rwhp at 1.2 bar of boost. And was running rich(10.5 AF), with a duty cycle of 95%.

Today i was out autotuning the car, and everything was working fine. And the tune was getting better and better. After about 25 min i did a low boost pull about 0.5 bar and the car startet to hesitate. It went realy lean, like 17-19 in AF. I checked it and it started running lean under vacum as well, even tho it was running fine on vacum a few min earlier. Then i reved it and dropped a gear and it was alittle richer again. About 14.8-15.9 under vacum and i gave it some gas and accelerated and it came back to normal af ratio. Then when i got to 5000 rpm and 0 boost it started going lean again. And it was like this if i tried higher revs, but if i droped it down to just above 3000 rpm it was fine again. When this happens the shound of the exhaust changes also alot. It looses the raspy sound the rotary engine has, and just goes more silent/darker. When u try to rev it with the clutch in it's so lean and the sound is strange as hell. Now this has happend a few times after the tuning. And when on the track 2 days after the tuning it would do this after 8 laps when it was raining and 3 laps when it was dry and the sun was out.

I have tried replacing the alternator, changing fuel filter. Put up a heat sheild between the downpipe and lower intake manifold. The downpipe is about 4mm away from the lower intake manifold. Wich is aboit too tight i know. Now i messured the LIM with a heat gun and it registerd a surface temp on the front runner of 185 degreece celcius. And the fuel rail was at 78 degreece celcius and the FPR was 68 degreece celcius. Now the fuel cell was colder then my hand so that was ok.

Now a picture to show how close the downpipe is to the LIM.




So if anyone has any ideas, have had this problem and fixed it. I would be so thankfull.

Could it be that the fuel is getting heatsoked so it waporises to fast before it get's into the engine? It must be something. The fuel pressuer is the same when this happens. Got a base pressure of 2.6bar at 0 boost.

JT

 

I could be way off, but it sounds like you having a sticking injector or dieing injector. Or, a bad air temperature sensor?

Way back in the day, I had a injector stick wide open. This was after I had RC clean them. Then they sat for 3 or so months, before installing and running them.

I also had a bad water temperature sensor, that caused endless grief. You can read all about it in this link. Well worth it imop.
https://www.rx7club.com/3rd-gen-archives-73/my-car-what-my-tuner-calls-problem-child-i-need-help-303500/

CJ

 

Hmm might be. I was just at the workshop and changed plugs. And started it up again. Now the car was almost cold after 4 hours. And it was the same now when i started it up. Wich it has never done. The injectors are over 3 years old. And i do have a spare set of the same injectors lying around. Maybe i should try and change out the pri injectors, since im having the problem even under no load, and even when ideling.

Could it be a ignition problem? Coils or CDI box having a problem?

JT

 

4 x 1680cc injectors 1.2 bar boost 95% duty does not sound right
Duty cycle should be a lot lower at that boost. So looks more fuel related.



rgds
Brian

 

Remember Brian this is with Ethanol(E85), so it will use 30% more fuel.

JT

 

map sensor is still connected, happened to me this weekend, had a bad hose with a crack in it.

 

Ok so it kinda looks like i solved my problem. I changed the primerary fuel injectors and put on a huge fan that covers the airfilter/turbo and blows cold air under the upper intake manifold and right over the fuel rails and fuel injectors. I was out driving the car for 30 min and no problems at all. Gave it a few pulls and saw that the AF ratio was abit lean, so i gave it alot more fuel under boost and higher revs and it responded verry vell. But i was maxing out the fuel injectors i saw, so i need to increas the base fuel pressure from 2.6 bar to 3 bar to get more fuel.

When i got back to the garage i checked the temps on the fuel rail and fuel injectors and the temps was about 35 degreece colder then yesterday when i did not have the fan to blow over the fuel rail and injectors.



Now i would need to retune the car and see what happens.



JT

 

Good luck, hopefully you solved your problem.

 

Thanks, i hope so too.

Ahh u changed your avatar pic, thank god. i was getting tierd of looking at those **** :P

 

it sounds like you need BIGGER INJECTORS! dont let your fuel pressure get out of control, its sort of a ghetto fix.

 

Dude have u seen my setup? I got 4x1680cc injectors now and a low base fuel pressure. It's at 2.6bar(38,2 psi). So im gonna turn it up to 3 bar(44.3 psi) base pressure.

And il be adding 2 more injectors next year. Not gonna bother about doing it this year. Im happy about running 1.2 bar right now.

JT

 

How does the Autronic control those 1680's ? Can you get a decently lean idle with injectors that big? Do you think it does a good job of injector staging?

 

Yeah it's quite good. I can get the car to idle at about 1300 rpm on my big bridge port. And a AF ratio of about 15. But i don't think it sounds good at all, so i let it idle at 1750 or so at 14 AF. Now this is with E85 tho. It might be easier to get it to idle with regular fuel.

JT

 

I think you need to look at your fuel pressure ! I had a bad experience wit the Aeromotive pumps before . Also , you might do well to install a fuel cooler.

 

Yeah a feul cooler is going to be installed. Could u explain more about your problem with Aeromotive fuel pump.

JT

 

At that time I had a half bridged 13B with a TA 51 . I was doing some road tuning with my tuner. Everything was fine up to about 12 psi boost and 6500 rpm's , after that point , the car would hold back and buck violently , whilst the a/f ratio would go way lean.He was almost wide on the injector DC trying to hold the ratios! Every time we tried to go past this point it would happen , I did not have a fuel pressure gauge in the car so we headed back to the dyno and did a pull to see what was happening . Turns out that the fuel pressure was falling as the boost and RPM's were going the other way until that "critical" point. I have since put in a pair of '044's and have had no problems at all. The pump was an A1000 taking suction from a gas tank sump. I also saw a couple other guys here have the same problem.

 

Other side of the spectrum, I ran a A1000 in my last 3rd gen for 5 years without any problems.

603 rwhp and 55 psi fuel pressure with a Aeromotive Fuel Pressure Regulator as well.

 

I killed an A1000 with 55psi static pressure very quickly. I attributed it's quick death to having too much restriction on the pump inlet filter (was using a small one so it would clog easily, causing pump to work too hard/cavitate). It also pulls alot of current and I didn't have great wiring to the pump. Knew there was something wrong when the pump blew a 25amp fuse. Replaced the fuse, but the pump was never the same again, would run progressively more lean with more rpms/boost.

I can't remember what size tank you were running, but I have had issues with fuel heat as well since I run a 5gal cel. Any extended idling cycles the fuel very quickly with the large pump, heating it up faster. I ended up putting in a cooler recently, but not sure how much good it is doing.

-Andy M.

 

Same here.
When you do the job right in the first place the problems are less likely to occur.
The Bosch 1600cc injectors should not be ran with less than 42-44psi base pressure especially when they are being pushed to the limits.

 

Yeah, I had the big Aeromotive Fuel Filter and dedicated wiring straight to the battery.

My new 1st gen, is also equipped with a A1000. I'll be adding a second one shortly.

 

The other thing to look at is the A1000 current draw vs. pressure as well as flow vs. pressure charts. Current can go up alot with pressure and flow can go down quite a bit. At 1.2bar fuel pressure is up above 70psi with a 55psi base pressure. Though you should be safe even if you are maxing out the 1600's (about 150lb/min*4 = 600lb/min). At 12V the A1000 can support that up to 60psi, and at 13.5V it can support that up to 80psi.

-Andy M.

 

I would like to share that I used the Aeromotive Eliminator and was pleased witht the performance. I even had their electronic voltage requlator. I'm in the process of changing the system to the 2 walbro intank units. I no longer want to run the external pump for personal safety reasons. I will be going with the CJ motorsports bracket and 2 -6 lines merging into one -8 line.. I will have more information to fallow.

 

However you achieved this I dont know , I guess maybe you got one of the "good " ones.
My pump was set up with a sump , -10AN lines ina an out , paxton regulator and an aeromotive filter . My idle pressure was 40psi , I ran 6 X 850cc stock injectors.
One of my buddies , experienced the same thing with his bridged 13B race , car . He had a TA51 , 4X1600's and a A1000 . I was on the dyno with him that day when we were trying to tune the car above 15psi , we had to keep upping the injector M.S. to increase fueling , but it still kept going lean as the revs went up. Another on looker saw the fuel pressure gauge on the regulator dropping as he boosted . He too did not have an in car gauge.
jantore , checking your fuel pressure under load cannot hurt . you will at least be able to rule the very real possibility that the pump is living up to its reputation.

 

How did he have the pump wired ? What size fuel line to and from ? What size filter ?

My pump was wired directly to the battery, ran -10 to and from the rails and had the -10 filter.

 

No, I was saying my A1000 failed quickly. Considering I hadn't done a great job on other parts of the system it may not have been surprising. However, I should add that it was the same setup I'd been running an SX Performance (similar specs) pump for a couple years on. I'd only switched over to the A1000 when I had a problem and was guessing at fixes. I've since put the SX pump back in and no issues.

Anyway, didn't want to diverge from original post too much. My thought was that is was fuel delivery related, and pump or restriction to the pump was the culprit.

-Andy M.