PETEW Posted January 17, 2002 Share Posted January 17, 2002 I am bickering with a guy over a '83 ZXT that he has for sale. The engine runs and drives (not inspected) but it runs rough. It does get better as it warms up, so I am confused. He said that its the 2 injectors that he put in, if I switch them it will run fine. I did notice that one of the injectors is a non-turbo injector (green body) the other I am not sure (it has a white body). I am hoping that running the wrong injectors won't cause more problems because of lack of fuel. Could the rough cold running be because of the wrong injector or is it something else like the AFM, or one of the million other hookups to the fuel rail. Please help. He is asking $800 so I am hoping to get a good deal. Thanks. Quote Link to comment Share on other sites More sharing options...
Len Posted January 18, 2002 Share Posted January 18, 2002 While you run the engine get a large screwdriver and place the slotted end on the injector and handle end at your ear. Listen for a clicking sound, the injector is working if its clicking. If not clicking that one could be the problem. Also unplug each injector one at a time. If engine runs rougher then that unplugged injector is working. If engine doesn't change them that injector isn't working. My injectors on my 83 280zxt are brown by the way......Good Luck Quote Link to comment Share on other sites More sharing options...
PETEW Posted January 18, 2002 Author Share Posted January 18, 2002 Thanks for the reply. I am pretty sure all the injectors are firing, though. The car runs rough when cold, but if you get on the gas hard enough that the turbo boosts up it seems to smooth everthing out. That is why I'm not sure changing the injectors will do it. If anyone has an idea, or had a similar problem please help. Last thing I want to do is buy the car and find major problems with the motor. Unfortunatley, my pockets aren't so deep. Thanks for all the help guys. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 18, 2002 Share Posted January 18, 2002 Has it/will it be compression tested? That's a sure way to make it run poor cold/decent when warm. Same happened to my zx. I lost about half compression on two cyls when I noticed it was burning oil.. about a qt/month, found there to be only 72, and around 140 on the others. It caused me to have a horribly rough idle when cold. I don't know so much as far as ZXT's, w/o the CS valve etc.. but it might be something for you to look for. Comp. testing isn't too hard, and you should be able to get a full ( yetextremely worth-while) engine diag. for 50-60 if you look for a deal. I found a used car inspection deal at a local shop for only $$52!! so anything I missed they could certainly catch. You might look for something similar around.. I mean an $800 purchase is any $800 purchase, am I right? good luck -980mak Quote Link to comment Share on other sites More sharing options...
Tony240ZT Posted January 18, 2002 Share Posted January 18, 2002 There's no doubt the miss matched injectors will make the car run ruff, and some reman's don't particlize the fuel properly and all of the fuel doesn't get burned properly. I think $800 is a great deal for the running car. The air flow meter can be adjusted to compensate for the richness by tightening up the pendulum spring slightly. The spring loosens up over the years. If you buy the car you can drop in some slightly larger injectors anyways for more performance. Might as well, it will probably cost the same for a used set of Mercedes 450SEL injectors as it will 280ZXT ones. I'd spend the $20 an injector to have them cleaned by RC. Once you stick them in you then need to mess around with your AFM to get things running smoothly. Having a valve job done to the car will probably help it run a lot better as well. You can get a gasket set for a 280zx non turbo for less money because the kit doesn't include the copper gaskets for the turbo. That is, if you believe those gaskets are in okay shape. I think I paid $55 for a Felpro gasket kit. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted January 18, 2002 Share Posted January 18, 2002 It could be mismatched injectors. Does the motor make any other odd noises? Id say for 800 bucks, as long as its mechanically sound (you can chase electrical gremlins later)its a good deal. As far as larger injectors... dont bother with the stock EFI system unless you do an IC and turn up the boost. IMO, the car wont run terribly well with big injectors and stock FI. The AFM can be tuned, but that thing will idle pretty rich. My bud did that on a turbo car with good results, but the exhaust burned your eyes at idle!! Whats ambient temp when the car is idling funny? I wonder if the cold start is somehow messed up too. Evan Quote Link to comment Share on other sites More sharing options...
PETEW Posted January 18, 2002 Author Share Posted January 18, 2002 quote: Originally posted by Evan Purple240zt: Whats ambient temp when the car is idling funny? I wonder if the cold start is somehow messed up too. Evan[/QB] I was actually thinking the same thing. It seems to smooth out as the car was warming up (we didn't get it up to full temp). When we drove it, it was around 40 deg outside. So it could be the cold start (but I heard that there are 3 things that control cold running ) When boost was up the car ran good, and pulled hard (when cold). My buddy checked compression on two cylinders while we were there and they both tested out fine. Hopefully it is just a combination of the injectors and a sensor. Anymore ideas keep shooting them my way, it's always better using a thousand heads rather than one. Quote Link to comment Share on other sites More sharing options...
PETEW Posted January 19, 2002 Author Share Posted January 19, 2002 Well guys, I think I am going to get the car. The guy agreed to sell it to me for $700. I want to get two injectors for it so I can change them and hopefully drive it home. Any one got two used injectors they want to sell? Thanks for all the help. Quote Link to comment Share on other sites More sharing options...
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