legacycentral bbs

driving to work today and the car starts to chug and buck. check engine light comes on than the car dies. i fire it up again starts fine. give it some gas but will not go if i go over half throttle. so i think its the tps. what would you guys think it is? i do have a JDM ej25 manifold and was wondering if the tps from that would work?

No reason to guess wildly. Pull the trouble code.

could you point me in the right direction on how to pull the codes?

http://legacycentral.org/library/literature/codes.htm


As Vik said, no reason to guess wildly, but it does sound like it could be your knock sensor.

Pull the codes and let us know what you find.

right after i open my mouth i found the link. thanks for posting them. just read them and will do when get home.

Cool. Good luck.

Oh, also, no, I don't believe the JDM EJ25 TPS will work. You can take a quick look at its electrical connector, though. If it has four pins, it should work. But if it has three then it won't.

Water temp sensor, five bucks.....

douglas vincent wrote:Water temp sensor, five bucks.....

no water temp sen one. i got. i reset the ecu also.
22
23
24
31
45
49

so what do you guys think?

Trouble code 45 (pressure sensing) will make the ECU cut fuel above about 50% throttle. n2x4's experience (see http://bbs.legacycentral.org/viewtopic.php?t=40426) seems to indicate it might do the same for code 24 (IAC valve).

You've got a mess of codes though. The presence of code 49 (wrong MAF sensor) seems to indicate some kind of spurious electrical problem, though; ordinarily the only way you get that code is by actually installing a JECS MAF sensor.

Not all those codes are active. The Hitachi ECU cannot run while code 23 (MAF sensor) is active. It's unlikely that the pressure sensing setup and IAC valve are both malfunctioning, so you need to figure out which one it is. You tried clearing the codes? With the clear memory procedure?

waiting for the car to be cool and pulling out number 14 fuse as i read. i do have a JECS MAF, but its not in. i did install it for a min or so, so might have made that code. i will redo my intake and vacumm lines. than clear the ecu and see what i get.

Don't bother pulling the fuse. Just do the clear memory procedure.

But, actually, now that I reread your first post, it sure sounds like the IAC valve. A pressure sensing failure wouldn't cause the engine to stall.

A main ignition relay acting funny can cause a ton of codes, but usually won't make the car drive poorly.

this is the 2nd IAC i have put in and the same problem.

about the main relay. sometime the car will not start, than 2 min later it will. i hear the click that the relay should be doing.

also what about the ignitor chip? could there be a problem there.

the person before me beat the firewall and re wired teh chip.

thank you guys for the help so far. always welcome for more inputs. i think i need to ge the intake done first.

Clear the codes then go for a drive in diagnostic mode. In diagnostic mode it will only need a problem to occur once to set a code whereas in normal running around it will take two or more instances of a possibly intermittent problem to occur before setting a code.

The car can run with any of those codes set. They record intermittent problems and the problem can have gone away entirely and the code can still be set.

Any bets on a bad MAF?

Possibly..

You replaced an IAC valve before? Was it throwing the IAC trouble code then?

Could be the IAC wiring in that case.

I doubt it's a bad MAF sensor. This is kind of related to n2x4's active thread about his ECU troubles.

Isn't there a method for checking the IAC and TPS with a Multimeter? Seems like I saw a thread on it (might have been in the FSM).

I only mention the MAF because I remember reading a post somewhere with a car that had stalling issues during all sorts of different running conditions.

-I would certainly check off the Pressure Exchange Solenoid, as stated above this shouldn't cause the engine to stall..just cuts fuel.
-If it were a bad Knock sensor as previously mentioned, wouldn't this just through the car into a limp mode?

Yes, you're right -- there is a basic set of tests in the factory service manual. The trouble is that they can't reveal intermittent faults.

If the ECU knows the knock sensor is bad, it does switch to its base ignition map, but the engine actually runs pretty well on this map, so it won't feel like it's limping.

You didn't say what "driving to work" involves. Hills? highway? city driving? What were you doing when it stopped? What was the weather like/ How far had you gone?

I'd check the fuel pressure and flow, check all the small vacuum hoses aren't split or falling off, check that there weren't any spark problems... wet ignition leads for instance.

Clear the codes and go for another drive.