s,s,s...

[jatibb]

stumbling,stalling,starting ......
long story short, rover started running rough a month ago. stumbling off idle and then spit a code 48. replaced stepper (aftermarket) then would start, if it did had to feather into throttle to rev up. checked intake and fixed a couple of cracked (minor) vaccum lines. woulndt start at all. finally started after unplugging battery and stepper, went to set base idle (per instructions) and wouldt come below 2000rpm with stepper unplugged. tried stepper off parts truck, no change. swapped temp sensor, tps,maf,remove and clean stepper housing,replace gskt,coil,capacitor,fuel pump, all off parts car that was running fine when parked. checked for vaccum leaks with carb cleaner (3 times, lots of spray) bought another brand of stepper and started on 3rd try. today started and let sit in driveway until warm. idle was searching up and down after warm, tried to rev and it stalled. very hard to start back up, if at all. will try again when cooled down. ive heard that aftermarket steppers are sometimes the culprit but i have used these for 6 years and never had a problem on my 92, this was the first with my 91. any ideas?? thanks
on another semi-related note, anyone done a carb conversion on a 3.9?

[ccec]

Hi,

Don't forget to check your "Air Gap" and other associated electrical goodies. This also could be an air mass sensor problem...

--Paul

[jatibb]

thats on todays list, plus a fuel pressure reg. swap from parts car. is there an easy way to check pressure? i assme you have to install gauge between regulator and fuel rail? it almost seems like it runs out of fuel when it stalls but revs up fine under load or sitting in neutral which, i think, should rule out fuel issue, ..??
would really like to get info on a carb swap. tons of info online but seems about 50/50 on either better or worse. i can live with the mpg if power is better. rpi seems to like the carbs but then again thats rpi so im sure anything they build is gonna be great. the argument for me being, i need cats, o2 sensores im sure (original i think,200k miles) did head gaskets in the winter and wiring harness coating is starting to crack all over. would love to open hood and not see all this "stuff" but not if i lose power and mpg. (both bad enough already)

[Paul Grant]

Rwgarding your thoughts on switching to a carburettor, I have had some experience in that area. I had an '85 RRC that came equipped with dual Stromberg 175CD's on a 3.5L engine. There was no performance. However, I eventually installed an Edelbrock Performer 500 (purchased from Summit Racing) on an Edelbrock manifold attached to a 4.0L long block, switched to a Mallory distributor and performed a few other tweeks and got power up to around 200 hp (according to conversations with Chris at RPI). Granted, an '85 RRC is a few hundred pounds lighter than an NAS version and I had an LT77 5 speed but I will say that the switch transformed the truck. Sadly, I seldom saw much better than 11 mpg but at the time gas was cheaper so it didn't matter to me.

[jatibb]

thanks for the reply. im looking for "real world" answers. if i keep this thing i may lighten it up and simplify it as much as possible, hell removing all the efi stuff would probably take off 200lbs. hehe. i think its just getting old in regards to the electronics. in the last year it has become very unreliable and frustrating. i love these things, this is the second one, still have the first for parts after trans went out i repaced truck for not much more than used trans. anyway, i only get 11 mpg now since putting on 235-85-16 and 2" lift. thanks again....

[ccec]

Hmmm...Sounds like maybe even a clogged fuel filter. Might as well go through the whole bit: Fuel AND electrical goodies.
What is your rig? a '91 Classic?

--Paul

[jatibb]

ended up being fuel pump, i had swapped it for the pump out of parts truck, which was fairly new when parked... 2.5 yrs ago. bought a new carter, fitted to original 91 housing and all is ok now. curious though, 92 model fuel pump housing has 2 weird things on the pick up and eturn lines, 91 does not. are they inline anti-back flow(is that a word?) valves? anyway i guess 2.5 yrs of sitting in fuel could ruin a fuel pump, even if not used.