iveexcaped3

ok so i did timing chain and head gasket replacement. timing marks lined up timing is dead on, 15 deg btdc idle is at 750rpm. fuel pressure is at 40psi running 30psi off. fuel injectors read 14 ohms each. fuel injectors are not clogged. that test passed too..... now for the problem..... when i rev the engine it tops at 5000rpm but when i roll the pedal into it it will rev to 6500rpm. i read every where no one had a solution, any thing will help thanks ka24E

Pro ViZIon

have your replaced your fuel filter? If you haven't i suggest getting a z32tt one.

Also have you check the sock filter on your fuel pump. could be clogged or the pump could be on its way out.

__________________
1990 Nissan 240SX w/KA24DE - New project
1984 Mazda RX-7 GSL-SE 13B

iveexcaped3

Fuel filter is brand new. Fuel lines, coolant hoses, and all vacuum lines are brand new. I was thinking it might be fuel pump but why would the fuel pressure be up to spec?

GroundPerformance

While it may not be fuel problem. I will tell you however that fuel pressure should be @ 43.5 with the Vac hose off. Also a dying fuel pump will start the car and build pressure on idle and low engine load how it reacts on full load is another story since the question is can it sustain the pressure consistently.

iveexcaped3

I'm doing a fuel pressure volume test today and see what I get. The plugs and wires are brand new as well to kill that question. I read some where the 5th gear sensor and I disconnect that and no difference there either.

iveexcaped3

Today I'm going to test the tps and mafs as well, ill let you know the results.

Edwin562

ever thought the ECU could be bad???

bb4_96

Doesn't sound like 5th gear sensor. On mine I couldn't drive faster than 90 and the 5th gear sensor fixed it. But it wasn't rev related like your problem.

iveexcaped3

Ecu wouldn't make sense nothing was done electrically to mess with the ecu. It's only when you rev it fast it'll tac out. if you roll the gas in it'll go past 5000rpm

blueshark123

ii had this happen to me but it was the tach that was bad but i dont think thats ur problem

iveexcaped3

I'll disconnect it today when I get to the shop to rule that option out too. If I remember right the tac was in sequence with the speedo the first time I fired it up but never after that.

iveexcaped3

tried the disconnecting the speedo/tac today no luck. also tested the TPS and the MAFS. ohm tested the wires just in case. then ohm tested the fuel pump.... think it might be my problem. so groundperformance ill give you your kudos when the pump is changed and running good again (if thats the problem)

s13tech

just because a component doesn't fail a resistance test doesn't mean its bad...voltage output much better for checking a sensor that has an output. sounds like you did eveything right vac lines, tune up, etc...you probably have but clean your throttle body you would be suprised big help sometimes

iveexcaped3

i cleaned the throttle body too. after i ohm tested the fuel pump i did a volume test as well and passed so that wasn't it which eliminates the fuel now its electrical or air I did a ohm test one the coil and it was 1.5 the spec is .7 then tested the secondary on the coil and it was low so i'm going to hook up a scope on it on Monday to test the coils activity when its active

x2fast2belegalx

id say itd be the fuel pump/filter. change both. i had the same exact issue with my car when i first got it. full throttle it wouldnt rev past 4500-5 without sounding like a limiter. but rolling throttle it would gladly go on past it.

iveexcaped3

Alright. Yesterday tested the coil and did voltage out put on the mafs I think that it will be my problem today I'm swapping mine out with a friends and it'll tell me right away. On the good side i found a ka24de for $100 bucks and the turbo set up $for it for another $100 stoked

jdm213

check your fpr, and ur fuel pump,

iveexcaped3

Did that. One of the first things I did. pressure is good and my fsm tells me to check the fpr along with the pressure test

blueshark123

Damn still nothing u tryy replacing ecu?

blueshark123

Is this car a automatic it may be something with your trans

iveexcaped3

Blue I think it might be my mafs ill find out soon. And not auto its a manual Trans. ecu doesn't seem logical to me.

iveexcaped3

well switched out mafs with a buddy of mine and his works perfectly fine. that wasnt my problem. im going to change injectors on friday and see if that helps. i broke 3 of mine replaced them from a junkyard car. it was a ka24e but not a 240 so im wondering if maybe it has a different pulse rate or some thing ill keep everyone posted if anyone has any ideas let me know

iveexcaped3

K replaced injectors with ka nothing. I have a theory.... If my distributor is off by one tooth and its arking on the cap from the rotor it would be one tooth to advanced and would be laying over because its not getting full spark. Can anyone confirm this or am I over thinking this?