Car hates running...

[kiefur]

Hey folks,

Started having some problems with my 93 and could use some help. After my transmission rebuild I thought that I was down on power, the car would run fine but it just didn't have the kick that I remembered. My mechanic said everything was OK so I put it down to driving my Viper more and getting used to its power delivery. After a few weeks the Lotus started to stumble a bit while I was in slow traffic (below 10 mph) I had to pump the gas peddle just to keep it running. On the way back from the mechanic (3rd time replacing rear oil seal) the car started running rough about 10 miles into the drive. If I took my foot off the gas it would die. It felt like I was running out of gas, I thought that the guage might be stuck so I coasted of the highway into a gas station and filled up. I only needed 8 or so gallons so the gas wasn't the issue but when I started the car it ran fine...... until I got another 10-15 miles down the road and then it started to run like crap again. It would clear up every few miles and run fine and then back to me having to pump the accelerator to keep it going. I checked the fuel filter and it looks good. Finding a mechanic where I live that knows what they're doing is not going to well so I hope that I have better luck with you guys.

Thanks in advance, Steve

[Sparky]

Could be many things, but here's something I've seen on a number of cars (not just Esprits) before.

If there's no check engine light or anything obvious, my first guess would be a buildup of rubbish in the tank(s) - the pump sucks this into the swirl pot at the bottom of the tank, eventually restricting the flow. Then, when you turn the car of, the rubbish goes back into suspension until you've driven a few more miles.

Only a wild guess - there are many other potential causes!

[kiefur]

Thanks for the heads up. I was thinking that the fuel pump was on its way out. Does anyone know how difficult is it to replace the pump.

Thanks..

[fflyingdog]

I cant remember what pump you have on the SE ,but on the S4s its in the right hand tank ,fiddly but pretty straight forward to replace.I have been through a couple pumps and i had the same symptons as you so not unheard of.It got the point where i had a spare pump in the boot just in case !

[Vulcan Grey]

I replaced the pump in an hour a few weeks ago.

But you should do the normal pressure tests before just believing it is the pump. Does it make pressure, and does it hold pressure after the car is turned off?

You should check spark, and resistance of the plug wires.

Rough running can also mean it is on only 2 cylinders. At idle, remove the electrical connection to the IAC valve and then pull one spark plug wire at a time and see if each cylinder drops the rpms by the same amount.

If 1 or 2 cylinders aren't running, then swap leads around (at coil and plug) and see if the problem follows the lead. If not the leads, then swap injectors around, and see of the problem follows one or 2 injectors. Since the injectors and coils are paired (1&4, 2&3) you must do most of the combinations to figure out the source of the problem.

To check the fuel injectors, I pull the rail complete, with the injectors clipped in, and let the injectors fire into a paper towel. Make sure all 4 make the same sized wet spot.