need renix help

I posting this up for a freind whos a member that doesnt have the time to post up here goes...
we replaced the blown head gasket on his 89 after he got back from moab it apparently let go somewhere out on the trail and he got it back home but soon after found the blown head gasket problem, also updated the brakes to a dual diaphram booster and new prop valve and in addition to that did the cooling system swap from open to closed or whichever way it goes..

Got it running tonight no air cleaner assy its going to have a k&n fipk adapted to fit the renix via a machined adapter, it also has no coolant temp sensor as it doesnt fit in the spot in the thermostat housing( its a huge metric thread vs a smaller american size)... the real problem is we cant get it to drive right after about 30% gas it wants to stumble and miss and backfire into the intake now we did correctly measure and adjust the tps for his 89 year using info from here(good stuff) his a and d measurements are 4.67 volts so using the 82% we set his b and d measurement to 3.82 and its not running right still??? WTF Any help with the renix gurus oh I almost forgot it has new fomoco 19lb injectors, along with pacesetter headers and a new 60mm throttlebody(renix of course)...

need some help here?? he did have to cut the o2 sensor wires to lengthen them with the new headers they were too short to reach the bung in the headers along with modding the hell out of the egr pipe to get it to fit...It seems to idle just a bit low and hesitates and stumbles a little after you pop the throttle sitting there and if ya pop it hard enough itll backfire for you... My thoughts are hes got a idle air control motor going( its still pulls just as much air with the throttle open as it does at idle) and it acts like a tps is going as well though all the measurements are good...

Check the rail pressure at the gauge. You can rent a fuel pressure gauge from autozone-they ask for a deposit but will return it if you bring it back in the same shape it left in. Sounds like a lack of fuel where it is needed most.

With no CTS, the Renix assumes coolant temp of 176F-per the manual.

I presume that on the 87-90 that the sensor that went into the radiator was the coolant temp sensor or is it on the side of the block down near the knock sensore? and if its got no cts sensor and its thinking its running rich itll be dumping a ton of fuel into the chambers...
thanks
keep em ideas coming

There are three temperature sensors on RENIX:

1) Driver's side rear of cylinder head. This one drives the indicator in the IP (lamp or gage.)

2) Driver's side radiator tank. This is a thermal switch, used only to activate the E-fan.

3) Driver's side of engine block, down by exhaust. This is the one that reports to the ECU. This may be replaced using a standard GM coolant temperature sensor with a 3/8" NPT thread, if you want to relocate it to the thermostat housing. (You shouldn't need to move the other two - but you can use a thermal switch in the thermostat housing, if you get one that trips right around 220*F or so.)

see i told him it was the e fan sensor he wont belive me, i have updated the radiator to a open system and no longer have a place for the e fan sensor in the radiator, so need to move something to the thermostat houseing, the oem one is huge and had to drill and tap out that big, anyone know of another sensor that will work? to trip the e fan.. this is only one of my many issues... thanks for the info Dan

BaronVonRoot said:

see i told him it was the e fan sensor he wont belive me, i have updated the radiator to a open system and no longer have a place for the e fan sensor in the radiator, so need to move something to the thermostat houseing, the oem one is huge and had to drill and tap out that big, anyone know of another sensor that will work? to trip the e fan.. this is only one of my many issues... thanks for the info Dan

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I'm sure it's been covered here before, but I think the part that some have used was the TFS from a 1980's Corvette.

If your parts guy has enough brain cells to form a synapse or three, have him get out the "Buyer's Guide" book for whatever their electrics line is, and flip through that. It should tell you the temperature where the switch closes (and opens, if it's different) and what the thread of the thing is. If it's a one-wire switch, it's self-grounding and you'll have to make that happen. If it's a two-wire switch, wire it up the same way as OEM.

low idle and backfire with throttle can be caused by MAP sensor not receiving vacuum or disconnected-- make sure it's hooked up and the vacuum line runs to the lower port on the throttle body and not the top one.

Shorty said:

low idle and backfire with throttle can be caused by MAP sensor not receiving vacuum or disconnected-- make sure it's hooked up and the vacuum line runs to the lower port on the throttle body and not the top one.

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Map sensor is pluged in, confirmed has vacume and it is in lower port and it is new...

If you pulled the distributor, I say you have a distributor indexing problem. You could also have all the spark plug wires rotated by one on the distributor cap.

old_man said:

If you pulled the distributor, I say you have a distributor indexing problem. You could also have all the spark plug wires rotated by one on the distributor cap.

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did not pull the distributer, and wrote on the cap as i pulled wires so I was sure not to mix, but will tripple check i got that right thanks

Had the same problem when I started my 88 after I rebuilt the motor. I had to reindex the distributor it was a tooth off and there is no way to move the distributor around. But after I did that it ran great.

lonecountryboy said:

Had the same problem when I started my 88 after I rebuilt the motor. I had to reindex the distributor it was a tooth off and there is no way to move the distributor around. But after I did that it ran great.

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i did not pull the distributer so it shouldnt have got off indexing however i did rotate the crank with the head off to check cylinders... but theres no way to get the indexing off without pulling the distributer in that case right?

Not unless the timing chain skipped a tooth. I would at least check it. Put number one cylinder at TDC and check the Dizzy it will only take a few minutes and then you can eliminate that from your list.

i planed on re stepping everything tonight thanks for ideas keep them comeing guys

ok this is what i have done so far and at a loss... replaced map sensor with one i had no luck, checked timing i am right on there so its not that... took off egr valve diafram is working properly, checked crank sensor, checked tps, checked O2, no luck i am at a loss
all i have done to this thing is... replace head gasket, didnt remove distributer, cleaned up head, cleaned up intake and valve cover replaced, added new fordms 5.0 injectors 18lb, installed a header, installed a 60 mm throtel body, put it all together and it backfires
it idles ok little hard to start driving i can drive all day with a granny foot seems fine start to hit the gas you can feel major power loss then the hesitating and the backfireing starts....
get off the gas and your ok.... stomp the gas get into higher rpms and it will rum a bit better and gets some power

i thought i had a fule pressur gadge but i didnt so havent checked that what else do i do???????????????
HELP dan

Did you change your plugs? Sounds dumb i know, but i did that once...Thinking my friend change them

brand new plugs