Dat Z Sun Posted July 11, 2013 Share Posted July 11, 2013 Ok I got my 280 to run, fuel pump is hooked up to a switch. When she starts, she starts right away, but revs up to around 3000 then bounces off 2500 to 3000 constantly and when I hit the gas she wants to die. I pulled the plugs and she is running very rich. And sometimes if I play with the gas pedal she will randomly rev very high past 5000 with the pedal pulled all the way up. I am pretty confused about this situation. Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 11, 2013 Share Posted July 11, 2013 You only have 5 posts and none of them describe the engine or car that you're working with. "280 with a fuel pump hooked up to a switch" isn't enough information. Quote Link to comment Share on other sites More sharing options...
tecreatta Posted July 12, 2013 Share Posted July 12, 2013 Clean your corroded connectors. That will probably help alot. Quote Link to comment Share on other sites More sharing options...
Dat Z Sun Posted July 12, 2013 Author Share Posted July 12, 2013 New Zed, what are you talking about, did you not read the topic of this thread, and there is a reason I didn't state the engine... It's stock. Do you not know what a stock 75 280 comes with? When it starts revving on its own it runs clean and smooth. Connectors do not not have that green oxidation on them, couple wire are chafed but all strands are still intact, that's on injector wires and tps wires. I read that there is something under the throttle body that has an adjustment screw and needs cleaned periodically, is that true? I didn't have time to check. Could it be the injectors get stuck open and just spay constant? Thanks for the replies. Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 12, 2013 Share Posted July 12, 2013 I wrote a whole funny thing about your excellent use of grammar to convey your lack of knowledge about your car and its engine but chose not to post it. Seriously, you write unusually well. Therefore: Find and open the FSM for your car from the link below and read the Engine Fuel chapter to understand the engine, and the Emissions chapter to understand the thing under the throttle body. Good luck. http://www.nicoclub.com/FSM/ Quote Link to comment Share on other sites More sharing options...
Dat Z Sun Posted July 12, 2013 Author Share Posted July 12, 2013 Haha. Thanks I have it downloaded, and know a fair bit of engines. I'll actually go head and read it probably on Saturday to see if I can understand it correctly. Might help me not have to use a switch anymore, hate wiring diagrams though. But why would it cut out. Ahhhhhh! Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted July 12, 2013 Share Posted July 12, 2013 Well reading the FSM is certainly a good start. You should also read the Fuel injection bible. Really it's not that thick, only a few pages, but it'll give you a really good understanding of the Bosche fuel injection. Once you get all that in your head, Rip it all out and put in Megasquirt. I am always impressed at how well an L28 Runs on a properly setup Megasquirt. You won't have to learn too much about schematics if you buy it already put together with the harness. DIYAutomotive... Now should you decide against Megasquirt, there's a few things you can test which could be making the difference you're seeing. First though, Why is your fuel pump on a switch? Is your harness all hacked up? That aside, it's great that it runs, but it's obvious your mixture is being thrown off. FIRST thing to check is to look for cracked hoses, missing hoses, cracked bellows to the AFM, stuff like that, since a vaccuum leak can cause the car to run poorly. NEXT, a good possibility is that your temp sensor or thermotyme is gone bad. If either are shot the Cold start injector could be dumping extra fuel where you're not needing it. This wouldn't normally cause that extreme of surging you described, but could definitely cause the rich running condition. check those couple things and maybe start with replacing the temp sensor. The thermotyme isn't cheap, but good used could be had for not too much. I'd imagine a combination of the CS injector dumping extra fuel and a vaccuum leak could together cause high RPMs but I don't think that's likely. Quote Link to comment Share on other sites More sharing options...
Dat Z Sun Posted July 16, 2013 Author Share Posted July 16, 2013 (edited) Thanks for all that info, I have a temp sensor somewhere, I have to find it, I ordered it a long time ago. Does the CS injector spray in pulses cause that would describe the rpm fluctuation. I haven't had time to read the FSM yet, and probably won't till next week cause my cousins wedding. The TB coupler is crack here and there but I taped it up like a mofo for the time being. I got one off a zx but the TB side of it seems too small... Edited July 16, 2013 by Dat Z Sun Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted July 16, 2013 Share Posted July 16, 2013 Well do some reading and see what you can figure. Also check your running fuel pressure. I suppose a regular Fuel injector could be sticking too. Is any one cylinder more fouled than the others? Quote Link to comment Share on other sites More sharing options...
9rider Posted July 17, 2013 Share Posted July 17, 2013 I got a 10 year - not running Z and took me full 2 weeks to make it run smooth - I think. My 2 cents: Install a fuel pressure gauge. This help a lot. 33 psi idle 36 when rev. Fuel filter check or change? Fuel line check ? Vacuum line ? I change all my vacuum line ( cost just 25 - 30 bucks) Fuel pressure regulator? Throttle switch position when idle and in rev position ? I read the fuel injection bible everyday until I dream and had nightmare about it. Good luck and sorry I am not major in English so spare me for typo or gramma . Quote Link to comment Share on other sites More sharing options...
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