ianmyers

What's up guys. Recently bought an 1991 s13 with a ka24de. Car ran great for about a month but recently its been giving me a few problems. Once in a while it will start and then immediately die about 5 seconds later. Each time I try to start it after this the car sounds like it gets less and less fuel until it wont fire at all, just cranks. I just replaced spark plugs so I'm assuming this is either the injectors or fuel pump?

Another problem is with the idle. When the car does start, it will idle around 1100-1200 (when cold) and then the warmer it gets the lower it idles. Eventually it will idle around 600-650, when it's fully warm. I'm guessing this is due to the MAF, Idle air control valve, or the injectors.

If anyone has any info on how to get this thing running solid again that would be great. Thanks

tauntdevil

You will need to troubleshoot the issue.

First start out with the first issue. The starting issue.
What is not working? Just because you changed the spark plugs, does not mean its not electrical. Pull out one of your spark plug wires, put the metal in inside of it near a ground source like your strut tower bolts or something similar, and have someone turn over the car to see if it sparks each time. Remember to pull the others as well so the car doesn't actually start.
Make sure not to have your hand near the metal pin as it will give you a shocking pain.

If those work, than that means you are getting spark.

Next, pull the fuel line hose off of your intake manifold and put it into a water bottle. Turn the key to prime the engine with fuel. If no fuel comes out, than your fuel pump is dead or the filter is extremely clogged. If a little comes out, then it may mean your fuel filter is clogged so pull it, and try to blow through it. If it is difficult to blow through, than there is a clog inside of it and you will need a new one. If it is easy, than it is clear and may be else where in the line.

If you have both of those, than it will be a compression/engine issue. Hopefully it is not.

Let us know what you find.

For the second issue, it actually is not an issue.
The reason it revs so high is because the engine is trying to get up to temperature as quickly as it can when you first start it. If you have been driving the car for awhile and it starts revving too high at idle when you stop at a light or something than it may mean one of the sensors like the temperature sensor or Maf sensor is reading wrong and to make sure to just clean them.

Hope this helps. Let us know what you find.

__________________

ianmyers

Thanks for the response. This information definitely helped. The spark plugs, ignition coil, and distributor are all working as they should be. The cap and rotor are also clean inside the distributor. The car died on me today and left me stranded so before I left I went through a few things to try and get the car to start. A friend of mine told me his fuel pump wouldn't work for him on his 89 hatch 100% of the time so he said tapping it a few times would solve the problem. I tried the same thing and my car started right up. Due to this I'm about 99% sure the fuel pump is the issue so I'm getting a new one and installing it tomorrow. I'm also getting a fuel filter while I'm at it to eliminate another possible problem. The car has 245,000 miles so I'm positive it could use a new filter.

For the second "problem":
I understand that the car idles high to warm up faster and then slows down once the engine is warm. My concern was that the engine was idling much lower (350-400rpms) than normal. Originally, the car would idle at exactly 1000 when at a stoplight and around 700 when I would put it in neutral while moving. Recently however, the car would idle at 600 while stopped, and around 500-550 while slowing down. I'm guessing this is also due to the faulty fuel pump because after I smacked it a couple times and the car started, my rpm's were back to normal.

Thanks again for the help. I hope the fuel pump solves my immediate issues.

ianmyers

UPDATE: Replaced the fuel pump last night. It was a piece of cake and all went well. I start the car and let it warm up/idle for about 8-10 minutes to make sure everything is running well. I drive the car a 1/4 mile down my street and it completely dies/shuts off. This happened at night so I couldn't do much investigation. Basically walked home and went back at it this morning since I had some time off from work and school. Found that the fuse for the fuel pump blew which is why the car shut off and died on me. Now every time I replace the fuse it blows as soon as the key is put in the "on" position. The car is completely stock so none of the original wiring has been tampered with. I also replaced the fuel filter today to eliminate another future headache. I'm wondering why the fuse keeps blowing even though the wiring hasn't been touched (besides the positive/ground on the fuel pump). Could the new fuel pump be defective and be drawing too much power causing the fuse to blow? Could the ECU be causing the fuse to blow? A friend of mine had a similar issue. Also, the relay looks fine that is associated with the fuel pump so I'm pretty stumped at this point. Any input is much appreciated. Thanks guys

racepar1

It sounds like you got a defective pump. What brand is it and where did you get it? Also check and make sure none of the wiring to the fuel pump got damaged and isn't shorting. As for the idle, the engine is supposed to idle higher cold than it does when it's warm, that's normal. Although yout claimed cold idle numbers are a bit high, and your claimed hot idle numbers are a bit low. Typically it should idle cold at about 1000rpm and hot at about 750rpm. I would clean the throttlebody. Clean the idle valves at the back of the intake plentum. And clean the connections for the MAF sensor and coolant temp sensor.

Realistically it seems that you have no clue how to diagnose any issues or possibly even what it means to diagnose an issue. Did you check the fuel pressure before you threw a fuel pump at it? You need to know WHY it would die on you occasionally. You didn't bother to figure that out and now it's screwed up in a different way. I would advise you to find someone in your area who CAN diagnose it and try to learn what you can as he does it.

ianmyers

Thanks for the input. I could obviously write more about what I did to diagnose the issue but I'm not trying to write a novel for each post on zilvia. When I replaced the fuel pump the start-up idle/warm idle were exactly where you said they should be, 1000 cold and 750 warm. I do realize that the car idles high to warm up and then lower once it has had a chance to warm up. I guess I just wasn't clear about that in my OP. My fault.

I based my diagnosis off of what I've read on here and a friend of mine who had the exact same issue. I brought up the ECU because his problem turned out to be a faulty ECU, which he replaced. I didn't check the fuel pressure before I replaced it which obviously wasn't a good idea based on what you're saying. I replaced it based on the fact that it would only prime 50% of the time, unless it hit it. After hitting it, the fuel pump would work as if it were new. THIS is why I replaced the pump. Now, I realize this probably isn't the best way to diagnose the issue but from what I read on here and what other 240 people were telling me, the fuel pump was on it's way out, which is why I started off by replacing it.

racepar1

Forget what jackasses on forums say. Don't throw parts at a car until you can PROVE what's wrong with it. Every once in a while you'll have to take a shot in the dark, but 99% of the time you can prove it. You NEED to make very thorough posts to get any sort of useful diagnostic help. Vague posts end up with jackasses spouting "throw this at it" or "throw that at it" " a friend of a friend's car had a somewhat similar issue in that caused it". You NEED to be specific. Diagnosing cars over the internet is almost impossible, I have no clue why that idea is so hard to grasp for a lot of folks...

ianmyers

I'll keep these things in mind for the future. Thanks for the info.