I searched, but didn't find anything really like this....

Just got my car back two+ weeks ago with a rebuilt streetport, and at the time I went non-sequential.

Now, if I get on the throttle too much it acts like it's getting a fuel cut when boost starts building - usually it cuts around 3-4 lbs but it can do it right @ 0 on the gauge or I "sometimes" hit 5-7 lbs, but that's a rare thing indeed. I also get a fuel cut @ 4500 rpm regardless of boost level.

When in neutral, I can rev past 4500 with no problem.

I'm pretty sure we took off a solenoid/some solenoids we shouldn't have; I DO have the airpump still, so what needs to be on there still? I can and will take it back to the guy that did the work for me, but if I can I'd rather try to find the problem myself since he's a bit of a drive away and is kind of backed up now.

I'm also pretty sure my TPS is pretty out of whack - I'll be working on that Tuesday. My idle is high (w/lights on it ranges from 1300 to 1900!), and it "hunts" unless I have the parking lights or some other load on the system. I'm also getting some bucking under 3k rpm, but that may be a bad ground. I don't think the TPS is causing this boost problem, though.

Otherwise, the car runs great It starts right up, no smoke, smooth idle and pulls quite strongly as long as I watch how much throttle I give it - even on ~2 lbs of boost it has a nice kick. I can't wait to get this problem solved and get some more miles on the motor!!!

That being said, I did none of the work myself, so DETAILED descriptions of where stuff is, etc would be greatly appreciated - pictures would be really cool as this stuff is new to me; after all this I feel it's more than time for me to start learning more so I can troubleshoot things myself. I figure if nothing else I can determine if we left off something we shouldn't have so when I do drop the car off again the troubleshooting part "should" be out of the way!

Thanks in advance!

 

Did you ever look at the diagram I gave you?

-Dub

 

I am about to rebuild my motor with a street port! What stage port did you purchase? And where did you get it done? If you do not mind me asking what was the rebuildprice witht eh seals you chose along with a street port? i found that I could get two peice two mm with a street port localy for $1,700. does this sound resonable?

post your first comment about the sequintial mod on the above thread about sequintial simplifying.

thanks, joe

 

I've "looked" at it - I just need to get out to the car when I have some time and try to follow it I'm just trying to get some extra input...just in case!

-M

 

First off... I wouldn't mess w/ your TPS much until you find your main problem. The idle hunt might be due to your main problem... not the TPS. Sounds like you have a vacuume leak or somthing.... I'd check diagrams and make sure all things that should be pluged are pluged... and so on.

 

A friend had a similar problem on his car. It all traced back to the primary injector seals. They seal between the very top of the center side housing (small groove) and the injectors tops.

Either he had used the wrong seal type or pushed them down into the opening. The photo he showed me looked like he pushed them inside the opening all the way down to the bottom.

This allows some extra air into the engine at idle with a corresponding increase of idle speed. When boost starts, it blows out the primaries along with the fuel and the engine goes flat/dead.

Yeah sounds like you did this or forgot them entirely.
My friend did it twice before he asked for help.

By the way, the drawing of them in the 1992 manuals show secondary seals being also used with the primaries; another Mazda mistake. If you followed that and did not know better, you are hosed.

 

I really don't think it has anything to do with my injectors. A) The guy that did the work has worked on FDs in the past (we had the injectors blueprinted and new O-rings were installed), and B) It will idle fine at the correct RPM, but not consistently. And then there's C): I CAN build boost, just not the way I should be able to.

For instance, the first 10 minutes I was out driving today everything was fine, even with my parking lights off. When it is idling high, if I blip the gas or turn off the parking lights it will usually drop RPMs to about 900-1000. It seems once the engine is good and warmed up the problem gets worse - that's how I know when the car is ready to go in the morning...I can sit inside and listen for the fluctuating idle!

Anyway, I'll be digging into the TPS in a few minutes. I'll let you know what I find there, but otherwise any more input on the boost issue would be appreciated!

 

I've thought that, too, but again I think they are non-related issues. We removed the double throttle and butterflies etc, plus everything was yanked out of the car so the TPS is quite likely out of adjustment. And if I test it and it's not, then I won't mess with it

 

Unless you dropped the UIM on the TPS, and then played kickball with it and then unscrewed it entirely and washed it with your underware...don't think it will get outta wack by just removing the UIM.

 

Who knows? It may have been dropped, etc. It probably sat in a pile of parts for about six months, then got moved when my mechanic moved his shop.

Unlikely, yes, but the bucking/idling problems seem to be pretty common symptoms of the TPS. Can't hurt to check it out - start with the simple stuff first!

 

Stock ECU.

Yes, I've heard all the arguments for getting one, but there are people running this setup with the Stock unit and it works. Mine doesn't.

Dub, my mechanic looked at your diagram and he says everything is the same as what we did.

 

Yo guys, so what's the solution to the fuel cut off at 3000 rpm when boost start kicking in? I'm having the same problem too, and I was told to put some back pressure back into the exhaust.... ? is that gonna work? then I was told to unplug my battery for 10 minutes to reset my ecu? but I don't think that worked.... Oh 1 BAD 7, do you get a loud back fire when your fuel cuts???

 

No backfire. I've only heard a soft "pop" once.

 

I just wanna say thx to you guys, I did that ECU reset, and it actually worked... car runs like a charm now! thx a lot!