So - I have been experiencing what I am pretty sure is a fuel supply issue. '05 Roadster runs fine at times but after high temps outside, she seems to choke out like not enough fuel. Get a surge at times between gears as well as a bogging down...... and then I know what is coming. No power due to no fuel!! I changed the fuel filter and no luck. I then changed the fuel pump. Ever since I changed the fuel pump, I can not get the car to start. The pump runs as it should when I turn on the key, and also runs when I engage the starter but she never runs. I thought that maybey because it was up pon the ramps it would not prime properly (reaching here)... but that was not it.
Anyone have any ideas?

Thanks in advance -
Kirk

 

Check the fuel pressure on the fuel rail or,
Force the fuel relay closed then see if it runs.

 

There is no "priming", we changed mine this spring (the old one was seeping gas thru its seams".
The car fired right up. Get a pressure test kit and, as DJ said, find out what your fuel pressure is.

This one is what I have, fits my Crossfire and my Ford Ranger:
https://www.summitracing.com/parts/otc-5630
Makes it as easy as checking tire pressure - the spec is 58 pounds +/- 3 pounds.

You should know that our cars do not monitor fuel pressure, so it can be bad and the ECU does not know it.
But since you said you changed the pump and it wont run, you either got a bad pump or you plumbed it wrong. }
Well, that or the filter/regulator is bad, IF this is fuel related. But you know NOTHING if you don't know your pressure.

 

Hey pizzaguy - thanks ......as usual

 

thanks for the help!!!

 

HI Guys - thought I had it licked................... but no. So I checked the pressure at the rail and, as I suspected, it was null, basically proving that the pump I put on was indeed bad. I have since changed it (Bosch AM) and it fired right up and maintains like 57PSI at the rail. When tried a test run, I had virtually no pedal. read that to calibrate the position sensor to the new improved pressure I had to slowly depress pedal to increase RPM and then hold for a few seconds and then slowly reduce. (basically moving pedal at he same rate as the RPM change) I do this two times. And the car ran great for a few days. Ran it slow ran it hard, dogged it at times, and it was awesome. Then yesterday about 5 miles into my morning commute, lost pedal again... basically depressing the pedal did not increase RPM or power. Limped along for a short bit, then turned the car off and restarted. It ran fine at that point till I got home and parked back in the carport.
So far I have installed new pedal/position sensor, fuel filter, and fuel pump (twice). What is next? I m not sure how to trouble shoot at this point. There are no leaks, runs fine most of the time, but I have no confidence to go more than a few miles at this point..... she may be looking for a new home soon..

 

What is the fuel pressure now? The way I read your post, you ASSUME you fixed the fuel pressure issue - but simply measuring it while it is running fine may not be enough.
I'd suspect pressure is falling at times, due to what ever reason. My point: Measure the pressure when it's acting up, if the pressure is low, you must chase down the reason, if pressure is fine, you have something else going on.

 

My money is on an RCM issue.

 

Certainly something to check... To the OP, pull the RCM open it up and check the Fuel Pump relay in the RCM. Could have a poor connection there with signs of burning at the points that may just require a little cleaning with emery cloth. Easy enough to pull and check the contact points in that relay for signs of burning or possible sticky movement. Here's the #4 relay you want to check inside and here's how to get to it... 2005 years Chrysler Crossfire: Locate and removing the RCM module

If you have burning at the points of contact from spark arcing it may result in a closed and open circuit at random that is cutting power and restoring it to the fuel pump at random. You stated, "Limped along for a short bit, then turned the car off and restarted. It ran fine at that point till I got home and parked back in the carport". When you shut down and re-start the relays open and close again so the act of shutting down and restarting may have caused the points to connect enough to run the fuel pump again (for a while) before the problem returns. If I were driving the car and experienced these symptoms and was stuck somewhere limping I'd pull over with the engine still running, open the hood and uncover that box to expose the RCM module and just give it and the box a few bangs with my hand and see if power was restored. A few bangs could also cause the points to resume a closed circuit again. If that worked and full power was restored for a bit I'd conclude my problem was there in that box and most likely that fuel pump relay in the RCM.



Youtube has videos uploaded on how to take the relays apart to expose the points and and put them back together. Pretty easy. Here's one...

 

Could be the fuel relay in the relay control module is going bad. Open the RCM and look at the relay coils (post a picture?). If the fuel relay coil is way darker than the air pump or horn relay coils, relay may need to be replaced.
I can rebuild your RCM if needed. Email tighed1@hotmail.com for the details.

 

thanks for the advice... I will be looking into the RCM as soon as I get a chance. Is it located at the firewall on the left side of the engine......near the battery with the 2 slide locks on it?

 

Yes

 

thx

 

Yes, that's the box that contains the RCM. Watch the video. I see you've installed a rapid disconnect on your battery so pulling and checking the internal relays of the RCM shouldn't be overly spooky. If you are spooked, just buy a spare RCM and try that or keep it in the car as many others do because the stock RCM has a tendency to fail and create the dreaded N0-Start problem due to failed solder joints that can come at any time. Even if you totally screw the internals of your RCM up you can toss in a new replacement and forget about it. Prices of these things tend to bounce all over the place and I see today it is $160 on Amazon that is quite high. I paid about $120 for mine and others have scored some as low as $90. You can search and maybe find a new SMP brand for less than $160 but even at $160 it's still not pricey when you consider what a tow will cost ya, the hassle of being stranded and then probably ending up at some Chrysler dealer that is gonna rape ya with technicians who know nothing about these Mercedes based cars.