Running Lean - I think

[bhermes]

I know that there are many posts on the topic of running lean and the fuel system. Just a quick note again to let everyone know that I am an extremely novice mechanic. I know that most of this stuff is in the FSM but when I read for the first time it might as well be in spanish. With a little help from this group and the FSM I can usually figure things out. So bare with me. I have had a little help in this area previously but could use a little refresher.

I just recently completed dropping my tank and coating. Tank had some rust issues.

Initial question, my car seems to idle best at 1000 rpms not 800. I have played around a little with the TPS. I know that the FSM stated that the idel speed should be 800 rpms. Any comments? Is it typical that the AFM's need to be modified. I am not sure if the cone shaped air filter would cause the AFM needing to be adjusted.

The car probably needs a tune up. I have replaced the plugs, fuel filter, cleaned the air filter (cone style).

Second question; I did not replace the fuel pump after recoating the tank and suspect it may be clogged/bad. It is a relatively new pump (less than 500 miles) but subjected to rust. I have been told that the inlet to the pump has a filter but not sure. I removed the inlet and really did not see a screen but not sure if I should remove the pump to inspect. If I remove I may just replace. I hate to replace parts that are not known to be bad. Do most after market pump have a removable filter in the inlet? The car during driving and acceleration what to die like it is not getting enough fuel.

Last for this post, can someone give me a little guidance on checking for vaccumm leaks. Where does the gauge need to go. I saw some posts about checking down stream of something and that vacumm leaks would be more prevalent at idle than running.

At the end of the day I may just have a fuel pump issue but hate to just blindly replace parts but it would be nice to rule this out.

Thanks for your help in advance.

[Zed Head]

The screen in the pump inlet can be hard to see since it is cone-shaped. I don't know why you think that pump might be clogged, but measuring the fuel pressure is almost always a good thing. It's one very important measurement that is good to know is right before getting too deep in to other stuff.

As far as the 1000 RPM idle speed, that's what my tachometer shows also. But I have measured my actual RPM with a meter and my tach is off by 200 RPM, so my 1000 is actually 800. I wouldn't worry a lot about it. If you have a multimeter that will measure DC frequency you can calculate your RPM off of the coil pulses.

[bhermes]

Only reason I am concerned about the pump is that I had a lot of rust in the tank and noticed a lot at the inlet of the fuel filter. Aft of the fuel filter seemed clean. I replaced the filter regardless but not the pump. The car would run fine for about a week or two and then just shut down. I assumed that the pick up line in the tank was getting clogged with rust and therefore I coated the tank. The only other thing I attempted was to adjust the tps and clean the air filter. I am going to adjut the rpms back up and see if the car runs better.

This is where my lack of mechanic knowledge becomes an issue. I would like to check my actual rpms but have no idea how to check the coil pulses? Any guidance would be great.

Thanks.

[siteunseen]

Vacuum gauge help http://atlanticz.ca/zclub/techtips/vacuum/. Search this forum for "yogurt cup test" for an easy way to find leaks by yourself.

[bhermes]

This looks great. I will begin to try after getting the instrumentation. Again bare with me but when they start throwing around abbreviations I struggle. A lot to learn and grew up a jock. Grew up driving a z back in the 80's and they were not old cars then (very little mantinance required). Just fast driving. Where is the FPR, I assume fuel pressure regulator. After the diagrams for the pressure gauges things get fuzzy. I will try the first part of this and see where things are. Can someone tell me exactly what the canister that the rpm gauge is connected to in above link does? How it works? My car would not start a few times and I noticed that the plug to the cannister was loose. The mounting for the cannister is striped. I added a clamp to tighten but not sure if ithe part is working correctly. What problems would this cause if it is intermitent.

Thanks

[bhermes]

Where can I get a rpm/dwell meter like the one in the link above?

[madkaw]

When you pulled the tank did you check the fuel sending unit pick up tubes to see if they were clear. Rust will build up in the tubes and clog it

[siteunseen]

That canister is the coil, if it doesn't fit snug it's probably not the original one, not a problem though. Standing at the drivers side front tire looking at the motor the Fuel Pressure Regulator will be in the center of the fuel rail, tube that goes to all the injectors, it's about the size of a 5oz cup with a small hose for vacuum and 2 or 3 fuel hoses connected to. In this picture it's about 10" down from the "C" on the valve cover. Small can looking thing with a lip around the center where it is joined together. Hope that's understandable, little fuzzy this morning.

Yes that coil has to be plugged into the center of the distributor cap, very important. I've seen zip-ties around that connection to keep it on the coil.

I got my vacuum gauge kit from walmart.com and would try and borrow a dwell meter, you want use it too much. I put a camera inside showing my tach gauge through a tv on top of my car.

Edited December 22, 2012 by siteunseen

[bhermes]

In regards to rust in tank lines, I blew air into all the lines coming from the tank and appeared to have good air flow through the tubes. Looked where I could. I took the line aft of the fuel filter and seemed to be getting good flow but not completely sure what good flow looks like. I am beginning to wonder if the FPR is bad. It just seems to be when I ask for high demand, acceleration, the car wants to die. Not really sure how the FPR works.

The coil connection on the wire coming to the coil seems not tight. Is this common or is it normally difficult to connect and disconnect. I am concerned that with all the moving of the coil prior to me clamping it down may have caused the connection to spread out. Is there a good way to test?

I think I need to start with the rpm and vacumm pressure checks and see where those are and then move onto something else if ok. Does this seem like the place to start?

In regards to barrowing a dwell meter I will try but I really do not know anybody that works on their own car. Hang out in the wrong circles I guess.

Thanks.

[siteunseen]

You could widen the round metal end under the rubber cap on the coil wire, it has a split. Or buy a new set of NGK blue plug wires, there will be a coil wire in the set also. You need a fuel pressure gauge for sure. Install it in the fuel line after the filter and before the fuel rail in the engine bay. Get one that goes to at least 60psi and you'll have to buy the fittings to make a "T" for it. Many ways to test things with that. Clamp the fuel hose after the gauge and you can tell if your pump is good, should go up to about 50psi. Remove the vacuum hose off the FPR and it should raise the psi's if the FPR is functioning right. A very smart man on this forum told me to put my gauge on 5ft of hose and zip tie it to the drivers side wiper blade so you can read it while driving. Note the pressure when your accelerating, coasting, and any other situations. There's a lot to testing these old cars but it's all been done 1000 times and talked about on this forum to make it easier. Good luck over the Holidays. It's a good excuse to get out of the house. Could you just have someone sit in the car and watch the tach while you test vacuum readings?

[madkaw]

Since you said you had rust issues you need to check the fuel sending unit. My zxt was doing the same thing and the sending unit looked new but had accumulated crap in the pick up tube.

The car would just die for no apparent reason. A pressure check would help prove this

[bhermes]

I am confued a little on the fuel sending unit. Not sure if all models are the same but I am not sure how the sending unit being bad would cause fuel delivery issues. Again, I am not that knowledgeable, but I thought the sending unit just sent a signal to the fuel gauge. My fuel gauge does not read properly or at all. Appears to be stuck on half full. I did clean the sending unit and check and it appeared to be working at least the best I could tell. Had a little trouble getting consistant resistance readings. As far as the pick up line I guess it could still be clogged but when I blew air into the line I could hear air flow in the tank. I initially thought maybe the pick up line may have had a hole causing air to get sucked into the fuel system. No real reason for thinking this just one possible cause of my possible fuel delivery issues. Finally settled on a rusty tank and it was definitely rusty.

Just a side note with qauges, my car was running 18 plus volts until I upgraded the alternator and rewired. Not sure if this may have played havic with my dash and particular my gauges.

Probably will not be able to check vacumm pressures and rpms for a couple days. The x-mas thing may get in the way and I probably should begin shopping at some point.

Thanks.