1985 Spider starts rough and dies

[Daveje]

I just bought a 1985 Spider that now won't start and run. It was running fine when I bought it, and I've have had it running OK a few times so seems to be somewhat intermittent. The car is in generally good shape with only 29K miles. I did pull the gas tank and flush it, the fuel coming thru the lines was real dirty looking(rusty?) Also changed the fuel filter,gas looks good and clean now. After that I had it running for about 20-30 minutes and then it would not start for more than 10 seconds and only runs real rough. The fuel pump will come on when I open the AFM door by hand,but is it supposed to come on just by turning the key on?(It's not) It seems like I only got it running good by fiddling with the coolant sensor connector, but that could have been just chance. If anyone has an idea on what to try next I'd appreciate it.

[msova]

I'm not familiar with the injection cars much, especially not the 85+ models...but start with the basics for ignition...fuel, spark, air....sounds like it could be fuel related though. Did this car sit for a loooong time? Perhaps there was already some grime between the fuel filter and the injectors and now its causing problems. Sounds like you got a nice low mileage deal....85's and 85.5's are pretty rare gems! Keep us posted!

[Daveje]

I think the guy I bought from drove it about 800 miles since he bought it in 2005. Seems like it's fuel related. It was running fine when I test drove it, and the seller said it started "sputtering" after he filled the tank for me. It seems like the fuel pump isn't coming on,although I know it works, but I'm not sure,gotta check some more. Could be dirt in the fuel or something after the pump like you say Marc although I did have it running great fora little while after the gas tank flush. If any one knows if the pump is supposed to come on as soon as you turn the key to MAR that would help me understand alittle.

[rlux4]

The fuel pump comes on when your ignition switch goes into "start" position. The arm for the potentiometer in the air flow meter moves as the flap is opened slightly and this sends the signal to the pump to run.
You can test the fuel pump running by turning the key to "run" position and take the air boot off the air flow meter, reach in and move the flap. You should hear the pump run each time the flap is moved.
Ron

[Daveje]

Thanks for that info. All seems OK with that then. Pump comes on when I push the flap. I tested the resistance to the sensors on the ECU ports and all seemed Ok except the coolant sensor, which should have read between 2000 and 3000 ohm but was reading about 1.2 meg(million) ohms. I don't know if this is OK. I did put a 3000 ohm resistor on the connector end of the sensor but the car still would not stay started.
It will start for a couple of seconds then shut off, no longer "rough" for whatever reason.. When I unplug the cold start valve it won't even do this, so maybe the injectors aren't coming on? I'll test those next but what tells them to come on?
Also, on the throttle position sensor, am I supposed to read 0 ohms or infinite ohm when I set this?
Hope I'm making myself clear hear.

[So Cal Mark]

sounds like the injectors need to be cleaned

[launieg]

I had the same problem (cold start injector works, but not others) and it was a bad ground wire (can't remember which one - cleaned up several). Start by testing to see if you get flashing juice to one of the injectors (other than the cold start one) while cranking the engine. No juice, probably a bad ground somewhere. Sorry I can't recall exact ground wire problem - I went through most of them. I was blaming the ECU, but that was not the problem. Hope this is helpful.

[So Cal Mark]

the two ground wires for the injectors are on the left side of the plenum. If the grounds are bad, you'll have power to the injectors but no pulsing

[Daveje]

Thanks, both ideas sound good. I'll start by testing the electrical tothe injectors and then on to flushing the fuel rail and cleaning the injectors since I definitely had some ugly fuel coming out of the tank. i'll let everyone know how it goes. I've got a timing belt, gaskets etc. coming from Vick Autosport,, dying to get this thing on the road.

[BrianAz]

I've just dealt with a similar problem. In my case after a major rebuild i forgot to reconnect the fuel pump ground which is located on the drivers side rear taillight (thanks Mark !). Check it to see if it is still making a good connection. With the ignition I would push the airdoor and could hear the pump running. However, the pump needs to find a ground somewhere (??) and hearing it running by pushing the airdoor does not ensure that it will run when the engine is cranking, with the cranking noise, cranking current and with the injectors working.
Your question: What makes the injectors open? The pulse from the coil connection (PUR) gives the injection ECU information about the engine speed which will activate the injectors.
Good luck,
Brian.

[Daveje]

Well, I disconnected the fuel lines last night, thinking I was going to start pulling the fuel rail and injectors, and decided to make sure there was fuel flowing. There's not, even though the pump was running. I opened the AFM door and felt the pump with my hand. Nothing coming out so I'm thinking clogged filter(even though I just changed it) or clogged metal line. Could be since I had dirty fuel problems and had to flush the tank.
Anyway, while opening and closing the AFM door at some point the pump stopped coming on and there was no voltage to the pump anymore, checked the fuse and it was still good.. I noticed that the relay by the ECU was "buzzing", I assume this is the pump relay? Looks different than the double relay I see in repair info. I see on this site, there are 2 relays back to back. Maybe the '85 is a little different. Wire connector ends look a little burnt. I took the relay to work with me this morning to try and test it. I'm not sure how though, I guess apply 12v to the negative and positive post and see if it clicks and if there is continuity between the 2 other post? So, first I have to figure out why there is no longer power to the pump, and then why there is no fuel flow. I just keep getting in deeper!

[narfire]

Well it might be a day late, but stop.... have a Guinness.... and continue. The only advice I can think of at the moment. Has worked for me in the past.
Good luck ,the car can be a never ending source of glitches but I've always (so far )enjoyed sorting them out.
Chris

[So Cal Mark]

pretty hard for the hard line to get clogged. More likely is a clogged screen in the tank or a kinked hose. The dual relays were all the same, unless someone has rewired your car and changed things

[Daveje]

The Guinness is always good advice, I'll get it running one of these days!
Is it possible the fuel pump is turning but not pumping gas? I know there is plenty of fuel coming out of the tank since I took a bath in it when I pulled the pump off over the weekend after flushing the tank. There is also a rubber line "S" shaped line from the filter to the hard line. As for the relays, don't know,hope I'm looking at the right ones since I know so little about this car. There were 2 back to back by the ECU and 1 was making a buzzing noise, only 4 wires going to it. This is an 85 1/2 car. Everything looks original and not butchered.

[BrianAz]

You mentioned that you had the pump off. Is it reconnected properly? As the electricial connectors at the pump are different sizes it is difficult to put them back incorrectly, so assume that the pump is turning in the right direction. Have you hooked up the lines as they should be? Check the fuel flow where the fuel should enter the fuel rail before you pull the fuel rail assembly off the vehicle. It is the connection nearest the firewall NOT under the pressure regulator, that is the return fuel.

Regarding the relay and the pump running when you push the airdoor with the ignition on, I had exactly the same problem. The fuel pump ran but then gave up, (because I did not have the pump ground connected) but I could still hear the relay clicking. Again, check the ground for the fuel pump, or make a seperate ground. If the relay is clicking and you have power to the injection harness, the relay should be OK. Check the voltage at the throttle position sensor with the ignition on to see if the harness has 12 volts.

Keep at it !
Brian.