[allansmith859]

Ok guys I pulled the 350 out of my 94 c1500 cause I thought the rear main seal was leaking. Anyway, I decided to keep the 350 setup for a roller setup someday and put a 305 in. Got it all hooked up yesterday and got it fired up. At idle it sounds great. When Im going down the road it sputters. I have the timing almost dead on, I got all sensors hooked up, I might have two vaccum lines crossed but it sound good. Also I broke my knock sensor when I pulled the engine out so I cant plug it in. I looked up what a knock sensor is it said it advances the timing until it detects a ping or knock and then retards the timing until the right air fuel mixture is set. It effects power and gas mileage. I dont know about gas mileage but power is an issue. Any ideas? could this be cause my knock sensor is not hooked up. Thanks guys

[69 widetrack]

Your knock sensor is the first place to start, if your timing isn't advancing as it should, power loss, performance and the effect your getting could be a result...good place to start and eliminate the obvious before you go any deeper.

[allansmith859]

Also I forgot to mention at idle my oil pressure is at 25 to 30 but when I hit the gas it goes to about 50. I know that the oil pump is good. I have always seen my oil pressure around 40

[69 widetrack]

I don't think that 25 or 30 pounds oil pressure is anything to worry about at idle...I'd get that knock sensor replaced and if the problem persists look else where. It needs to be replaced regardless.

Ray

[gearheadslife]

fyi you can't use the 350 knock sensor in the 305..
get one for the 305 cid

[69 widetrack]

1994 C1500, 5.7 liter knock sensor....$32.10 Just one link below.

94 1994 GMC C1500 Knock Sensor - Engine Electrical - AC Delco, Delphi, Standard Motor Products, Left, Right - PartsGeek

[69 widetrack]

My bad...re read the post and he did put a 305 in...appologies

[gearheadslife]

Originally Posted by 69 widetrack

1994 C1500, 5.7 liter knock sensor....$32.10 Just one link below.

94 1994 GMC C1500 Knock Sensor - Engine Electrical - AC Delco, Delphi, Standard Motor Products, Left, Right - PartsGeek

thats great, he installed a 305

[69 widetrack]

Originally Posted by gearheadslife

thats great, he installed a 305

My apologies again...I misread his original post and screwed up...as soon as I sent the post it hit me and I retracted my statement...damn I hate it when I do that.

Sorry about that
Ray

[Valkyrie5.7]

The correct for a 5.0L is $20 on rock auto.

[allansmith859]

I am using the knock sensor that came on the 305. I take it that its a 305 knock sensor. Also there is nothing wrong with putting a 305 in this. It is far from a performance engine. Beside I am using the roller block that came out of it (350) and going to do something with it cant decide yet. Might put it back in the truck with HEI System. But anyway I got a new knock pigtail and got it plugged in. Dont Know if that knock sensor is good but guess i should get one. Got all my vaccum lines hooked up right, all my plug wires are right, distributor cap is right, got new plugs and wires, and this thing is missing. I said before at idle its fine but i take that back its not. its missing all the time. Keep in mind it wasn like this before. This is why I hate ****in computers. all the money I got in this son of a ***** I coulda just went to hei and got better results, except for gas mileage

Anything else that could make it miss like this. Think it could be the harmonic balance is not right. this is the one I got with it but the block is bored 60 and it looks like a stock balancer. Maybe could try a 350 balancer or maybe Im just thuinking to ****in hard. What ya think guys, Im bout to roll this peice of **** in the lake.

[oldbogie]

Originally Posted by allansmith859

Ok guys I pulled the 350 out of my 94 c1500 cause I thought the rear main seal was leaking. Anyway, I decided to keep the 350 setup for a roller setup someday and put a 305 in. Got it all hooked up yesterday and got it fired up. At idle it sounds great. When Im going down the road it sputters. I have the timing almost dead on, I got all sensors hooked up, I might have two vaccum lines crossed but it sound good. Also I broke my knock sensor when I pulled the engine out so I cant plug it in. I looked up what a knock sensor is it said it advances the timing until it detects a ping or knock and then retards the timing until the right air fuel mixture is set. It effects power and gas mileage. I dont know about gas mileage but power is an issue. Any ideas? could this be cause my knock sensor is not hooked up. Thanks guys

A 1994 would have computer managed Throttle Body Fuel Injection (TBI). These are mapped in a PROM chip specific to the engine size and vehicle configuration. There is a lso a high probability that the injector size (flow per hour) is different. Basically this is a way of saying that a system programmed for a larger 350 will overfuel the smaller 305. Not to say there are other issues but this is a big one all by itself.

Bogie

[gearheadslife]

Originally Posted by 69 widetrack

My apologies again...I misread his original post and screwed up...as soon as I sent the post it hit me and I retracted my statement...damn I hate it when I do that.

Sorry about that
Ray

it happens, just didn't want the o/p to get the wrong part

[gearheadslife]

Originally Posted by oldbogie

A 1994 would have computer managed Throttle Body Fuel Injection (TBI). These are mapped in a PROM chip specific to the engine size and vehicle configuration. There is a lso a high probability that the injector size (flow per hour) is different. Basically this is a way of saying that a system programmed for a larger 350 will overfuel the smaller 305. Not to say there are other issues but this is a big one all by itself.

Bogie

you are correct.. bigger injectors and different prom.. iirc same ecu..
shouldn't be all that hard to find a 94 truck/van with a 305 to grab the prom and tb

[cobalt327]

Pull the plugs and inspect them to see if it's running too rich. Be sure the vacuum lines are correct and everything is holding vacuum, no vac. leaks.

These engines need to be timed in a specific manner, not just turning the distributor while using a timing light like non computer controlled engines are timed.