4.9L efi conversion questions.
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Cross-Country
Joined: Sep 2009
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From: Ogden
4.9L efi conversion questions.
Hey guys I'm in the middle of the conversion. I have a 90 efi system and an 80 f100. The donor truck threw a rod so i reap the benefits. I will be using the new (to me) head and my 1980 block most likely (just for bracket mounting and ease etc).
I see nothing different between the blocks that I know of besides the knock sensor. What have people done in the past for this sensor to be transfered over to the carb block?
Also there is a switch on the right rear of the block under the intake, just curious as to what it is.
Also is there anything else to worry about the difference in the blocks that I am unaware of?
Thanks.
Drew
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I see nothing different between the blocks that I know of besides the knock sensor. What have people done in the past for this sensor to be transfered over to the carb block?
Also there is a switch on the right rear of the block under the intake, just curious as to what it is.
Also is there anything else to worry about the difference in the blocks that I am unaware of?
Thanks.
Drew
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which truck are you using. i hope its the 80 your fixing up. and which motor threw the rod if its the efi motor just scarp the motor the heads on them like to crack if their over heated anyway maybe save the block if the walls went chewed up. and if you want to put efi of the carb motor i dont kno how much you like headaches because its gunna be a big one. i would stick with the old school setup. more reliable and less to break. and also that sensor your talking about under the intake is your temp sensor. weird spot they put it in. and remember these motors are dime a dozen still.
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Cross-Country
Joined: Sep 2009
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From: Ogden
ok I thought the temp sensor was off the thermostat housing. I appreciate the advice about not using the efi but its already in the works. And yes ive considered carb. But I like the reliability of efi. I dont have good luck with carbs. Yes the 80 is gettin the efi.
The most important question I have however was about the knock sensor below the distributor. What do you do to move that to the carbed block?
The most important question I have however was about the knock sensor below the distributor. What do you do to move that to the carbed block?
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Joined: Mar 2011
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it would have to go to the machine shop to be drilled out. or you could just swap engine blocks. also all 300 engines are all the same. there is little things that differ but all main parts are swappable.
come to think of it their might be a threaded plug that sits right below the distributer i remember seeing it on my engine. never thought of why it was there. check it out you might get lucky and be able to thread the sensor right in.
and the sensor that is in the t-housing is a temp sensor that the computer reads
come to think of it their might be a threaded plug that sits right below the distributer i remember seeing it on my engine. never thought of why it was there. check it out you might get lucky and be able to thread the sensor right in.
and the sensor that is in the t-housing is a temp sensor that the computer reads
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Cross-Country
Joined: Sep 2009
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From: Ogden
Ok so I'm back. I've got it all together. Spliced the 90s harness into the 80s harness as bet as I could. I started her up and she runs! But if I shut it off, it won't start again. I think the coil isn't putting out enough but its not the coil itself. I put the new one in and it still wont start.
I cut a lot away in the harness also so I feel like its on the primary circuit. Is there anything required on that circuit that could cause that? Perhaps the noise cap diode? I cut that out.
Also I don't have the o2 sensor hooked up yet so I'm thinking that may be related also bc it only starts maybe in a pcm commanded cold start. Any suggestions?
I cut a lot away in the harness also so I feel like its on the primary circuit. Is there anything required on that circuit that could cause that? Perhaps the noise cap diode? I cut that out.
Also I don't have the o2 sensor hooked up yet so I'm thinking that may be related also bc it only starts maybe in a pcm commanded cold start. Any suggestions?
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