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-   -   strange start-up problem (https://www.rx7club.com/1st-generation-specific-1979-1985-18/strange-start-up-problem-295270/)

Forgie 04-15-04 07:46 PM

strange start-up problem
 
my car wont stay running. it's an 84 se. it starts up, rpms go to about 2500 then fall quickly until the car stalls. this all takes place over about 3 sec. and I can hear a slight clicking noise coming from the intake. can anyone help me out. the car was running yesterday. I don't get it

Forgie 04-15-04 08:24 PM

alright well I cant hear my fuel pump. would the car start at all with a blown fuel pump?

BigJim 04-15-04 08:29 PM

its hard to hear the fuel pump cause it turns on only when the engine is rolling over, unlike other vehicles where it comes on when the key is turned on. check for vac leak and adjust idle and check plugs and watnot. Compression also

Forgie 04-15-04 09:06 PM

ok.......not fuel pump.......the car will stay running as long as I pin the gas and the rpms stay above about 5000. when it drops below that it just dies right off.

Forgie 04-15-04 10:45 PM

c'mon.....someone help me out here

hornbm 04-15-04 11:05 PM

Sounds like a big ass vacuum leak to me, but I'd check the TPS adjustment, and make sure the AFM is working right ond no wires have broken.

It also might be helpful to pull the engine trouble codes to see if you have one.

sweetege 04-15-04 11:09 PM

something could be cloged have you taken any emissions junk off yet or are you even getting air? anyoneelse that knows a little bit more bout FI motors would help.

LongDuck 04-16-04 01:48 PM

Alright I'm on it;

You're obviously getting spark (or it wouldn't start), so you need to look into Air and Fuel. Engines need these 3 things to run - Spark, Air, Fuel.

Fuel:
You stated that you checked the fuel pump and it is running - this supports that it would run at all. An EFI car won't even start without fuel pressure - it will just crank and crank. No fuel pressure means no fuel injected, means no fuel to burn, means no start. That you get it started at all suggests that it could be a crimped fuel feed (or return line), a bad Fuel Pressure Regulator (FPR) at the EFI fuel rail, or a bad Pulsation Dampner (PD) at the other end of the fuel rail. PD's rarely go out, and the FPR is pretty solid as well. Other thing is to change (no way to check without the right tools) your Fuel Filter at the rear corner in front of the fuel tank, right next to the pump. A clogged fuel filter will result in not enough flow to support higher rpm running, and will cause high rpm 'fade' followed by conditions as you've described. Change it - at $35 it's cheap insurance.

Air:
If the fuel system checks out and you're getting good pressure, start looking at the air intake path. Check your air filter for any debris that might clog the filter. Take off the airbox and look into the feed tube that goes in front of your radiator - look for bird nests, newspaper, etc. Remove filter and look down into the AFM. With keys in the 'on' but not 'start' position - push in on the AFM 'door with a pencil - you should hear the fuel pump kick in and a 'hissssss' from the fuel rail and injectors. Not much else to do with Air, since you said it was running the day before.

On Spark;
Pull your plugs just to see if it's flooding. Probably won't be wet, but if they are, here is where we switch gears and start looking at other potential problems.

Hop to... report back...

cdrad51 04-16-04 02:06 PM


Originally posted by LongDuck
Change it - at $35 it's cheap insurance.


You mean $3-5 right? j/k. But seriously is only about $23

Forgie 04-16-04 03:37 PM

alright......thanks long duck. yet again you've made my day. it turned out to be the connection in my air intake hose, the one right after the afm. it wasn't compleatly connected. and it was pulling air from the gap in the hose. it's always something so simple it seems.

Snapshot 04-16-04 04:39 PM

Choke ain't right. Try pulling it all the way out & keep pulling while you start. One of mine is so picky about this.

heb09 04-16-04 05:32 PM

I wish i had a choke.

Forgie 04-16-04 05:59 PM

yea........there's no choke...........and I fixed the problem anyway


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