Caver Dave

Details:
'74 AMC 304
TBI parts & harness JY takeouts from '89 2500 4x4 5.7L
Running MotorCraft dizzy (disabled vac & mech advance, but never moved/timed) feeding externally mounted EST (mounted/grounded within 1/2" of the GM coil + AL heatsink)
TB w/ 5.7L injectors mated to 2V intake with homemade adapter
Running EST, CTS, ESC (sensor in block drain), & MAP... NO EGR, VSS, or Oil Press.
Followed Bill H.s writeup from the Binder boards
Crank signal (C9?) connected to the Ferd style solenoid "S"

Initial start:
Had fuel but no spark. found a post by Docvette (RIP) on hotrodders.com that lead me to find a mistake I made in the coil wiring... tach signal was grounded. Pulled tach signal from ground and attached to SunPoo tach... fired right up after 2 revolutions! VERY rich on the ASDU 5.7L bin/chip.

Data:
WinALDL shows everything was good, no bad codes. For the first 2 weeks of running in garage (while the harness was being buttoned up), it continued to fire first turn. Got in a 5.0L manual chip (better starting point for datalogging to narrow down the fuel tables) and made a couple data runs of 10-15 miles. Under heavy load (large hill + WOT) got a few knock counts then ESC threw 43 flag. Started troubleshooting that is when I found I was getting no adavance.

Timing:
Several AMC folk told me to set base at 10* as they (AMC engine) liked it better than 0*. However, I'm unable to get it to start with the EST bypass unplugged! It will also die if the bypass is unplugged when RUNNING. Timing light showed 17* BTDC in the original (unmoved carb) position. Bumping this to 20* is better, but has hesitation on acccel. 30* runs much better, but doesn't like to start (too much advance for starting?). Regardless of where it's set, I get a little wiggle as RPM increase, then it settles back in at where it was set. 10* idles rough, but I do get about 5* of advance.

EST has tested good 4 times (OTC x 2 & Wells X2). Spare ECM (w/ same chip & Z1 perf. 5.7L chip... no OEM chips left, sent to bud as tuning fodder) show the same thing. SES bounce has been good for all chip/ECM combo, so it doesn't appear to be SA table related. EST & ESC have been swapped for more JY take outs with no change in advance.


Additional:
Harness (save a couple wires [coil connector & IAC plug] to correct JY hacking) is uncut, with unused circuits preened. All wires from ECM to EST & ESC have been rang & ohm'd as good. Key On voltages are good across board and EST running voltages (D4/D5) are good. With knock sensor unplugged (guessing it may be reading knocks & retarding) there's still no advance. Grounds are all to body mounted stud, connected direct to battery. FP is at 13# constant.
Starts have gotten VERY hard in comparison to initial starts. WARM starts require partial throttle. Injectors pulsing appears to be erratic during cranking, pointing to bad ignition process.

Read that a few folks (w/ NO timing advance) had pickup issues, swapped the wires, re-timed (too much advance) & were golden. Swapped the leads from the MC pickup/coil in dizzy to pins on EST & it ran like butt. I was unable to keep it running (lot's of spitting/sputtering) without manual throttle manipulation and fire timing light/twist dizzy...

Possibilities:
Grounded tach signal fried something (in both ECMs)?
Accidentally pulled the coil wire off coil and forgot to replace, spark arc'd to bracket above coil where the EST is mounted. EST checks good, but still fried from 50K volts?
Pickup wiring to EST?
Other ideas?

I will be happy to check/test/confirm/answer ANYTHING I've neglected to report or have missed! TIA!

dr.fiero

Need more info to really tell.... Hahahaha....

Ok, if you put the timing light on it while it's idling, and have someone pull the EST bypass plug, does the timing shift back??

That initial timing thing you were mentioning is pretty much based on what is set in the ECM. I have 10* set in mine.... but I have 10* plugged into my ECM! I could set 20* I'm sure. But I'd have to tell the ECM what I'm doing.

Caver Dave

NO, the engine shuts off! On occasion, the injectors will continue to pulse fuel after the engine stops rotating... Scary!

I'd be ecstatic to set it at 0* with the bypass pulled... if I could get it to start OR run with it disconnected

dr.fiero

Well, it really sounds like all the bits are there - they just need to be put in a row.

Have you done the 'normal' GM thing yet, with with pulling the EST wire, then setting the base timing to 0*? Also, confirm your balancer hasn't slipped!!!! Make sure TDC on the balancer really lines up with the 0 mark when you're really at TDC.

If you can pull the lead and it stalls - thats telling me that you do have some timing control.

Caver Dave

NO! I can NOT get it to start or stay running with the EST bypass disconnected! I do HAVE spark at the coil (haven't checked for fuel) with the bypass unplugged though. IOW, if I disconnect the tan/blk wire, it will NOT start. When running, if I disconnect the wire, the engine dies... and sometimes injectors will continue to pulse (squirting fuel) AFTER the engine stops until I turn off the key.

I did this last night.
- #1 run to TDC (by hand to confirm compression stroke)
- Timing mark on balancer was dead on "TDC" mark on the timing cover
- Rotor pointed to #1 post on cap
- Reluctor perfectly centered on coil pickup

If it matters, the Ferd cap has standard posts, but the rotor tip is 1/2" wide (unlike the rotor in the Chevy dizzies I robbed the ESTs from)

dr.fiero

Ok, you get points for thoroughness.

Try pulling the est wire, then start advancing the distro until I runs. Sounds like the AMC just doesn't like to run with that little initial advance.

Side note; the pickup coil actually sets off spark as the reluctor tip just passes the magnets tip (mag field collapsing in the coil), not pointing at it.

Caver Dave

So, you think the timing advance *IS* working, just not able to advance far enough to suit the AMC mill? Like the SA tables are maxing out, but it still isn't enough?

I started to go there last night, but it was very unhappy (spitting/popping thru the TB) and didn't need the hair scorched off my arm (... again ). I'll recruit some help for this evening and give it a shot. Can any damage occur trying to start it like that (outside of pre-ignition & fireballs from the TB)?

Caver Dave

OR could it be advanced too far and the ESC is dragging it back down

dr.fiero

It's highly unlikely the esc is pulling huge timing out. But you could pull the wire off the sensor for testing only (that'd rule it out anyhow).

As long as you don't get so much back spitting that you torch the tbi it'll probably be ok. There's no power valves (ala old holley carb) to pop. I don't think it'll be able to damage the map sensor.

Keep a water soaked rag nearby just in case though.



Are you going to be able to burn your own tune here?
It's sounding more and more like you'll need to.

Caver Dave

Hopefully I'll have some assistance "reading" the data & figuring out what to tweak.

A bud has a burner. Unfortunately, he's a couple hours away, so we've been doing them via snail mail. IF the timing issue can be resolved, I've got plenty of time before I *need* to have it drivable...

RFmaster

Caver Dave

You should be able to start and run your engine with EST connector open, but this may require manual dizzy adjustment! Once engine is running ok, with open EST, measure timing with a timing light. I assume that you have near stock 304 AMC - no wild cam, or mountain high compression. I would also re-verify timing indicator as suggested by dr.fiero. Probably, I would shoot for about 10degrees and about 600 to 650 RPM

ASDU calibration calls for 0 degree base SA advance. At idle ASDU calibration has 0 degree initial spark advance and will command SA to 26.02 (600 RPM/35kPA MAP) degrees advanced. In your case if your total advance can be = 10+26 =36 (at idle). Maximum SA is around 41 deg!. With this much advance you may have adjacent cylinder post cross firing (if you have a small hat dizzy). You'll have to modify ASDU baseline bin once you figure out what your engine likes to see for initial timing advance.

Another critical area to attain proper dizzy - EST module operation is a rotor phasing. Basically make sure that the rotor is positioned under correct terminal in the cap when the coil fires. GM reluctor coil produces a zero crossing voltage as shaft mounted magnets rotate within coil circumference creating alternating magnetic field. Basically, you have to make sure that the rotor is aligned with the correct terminal in the cap at the moment the coil fires. Which essentially means making sure that the pickup, rotor, and cap are all in alignment with each other.


//RF

Caver Dave

Confirmed that she'd still fire up/run with the bypass CONNECTED (timing light shows 20*BTDC) and shut it off...

- Pulled knock sensor lead
- DISCONNECTED the BYPASS
- Turned key to RUN & used remote starter to spin it over and...

NO flash from the timing light at all!

Further testing (BYPASS DISCONNECTED) shows it only gets spark to the center post of cap for the first couple revolutions, then NO SPARK!

Also, pump continues to run & injectors pulse (enough fuel to completely FILL the venturis above the butterflies in 2 seconds!) after trying to crank with the BYPASS DISCONNECTED.

dr.fiero

Well! As you might well tell... something is NOT right here!

The ECM is out of the loop until you hit about 400rpm. That's probably where/when you see the spark start/stop.

Lets back up a bit... what ECM do you have? 1227747? 1228746?

RFmaster

ASDU bin is a truck calibration running on 1227747 ECM

Yes, lets dig into it a bit deeper. When engine is turning over (under 400 RPM ECM keeps EST module in bypass mode) the pulses are amplified and shaped by the ignition module. These pulses are used to drive the circuit creating a magnetic field in the ignition coils primary winding that, when collapsing, will induce a high voltage in the secondary winding. Therefore, for evercoil pulse, the ignition coil is triggered. This is known as the bypass mode or EST module operation. In this mode, the engine is running on the timing advance that is built into the ignition module, usually fixed around 10 degrees.

ECM will only pulse injectors if it sees DRP pulses coming from EST module on ECM Pin B5 (purple/white wire). If you are not seeing spark check ignition coil and DC supply / wiring to ignition coil. Check spark at the coil HV terminal before it gets sent to dizzy hat. You may have phasing problem which I have mentioned in previous post.

Can you post closeup photos of your dizzy / Coil setup? Use free photo hosting service and just paste links into the post for hi-res shots.

//RF

Caver Dave

Thanks for your assistance Dr.f & RF! Bill's been diligently working with me though this entire install, but I felt guilty "loading" his plate with my issues, so decided to post here for a broader knowledge base on this issue

Yes, running the 1227747 ECM (mine are from '89 2500 4x4 5.7L & '89 1500 Suburban 5.7L) & currently the chip is loaded with ARPC (1991 truck 305 manual) bin. Getting SES "bounce" at key on, so that kinda rules out bad burn/chip, correct?

So, under 400rpm, it's running in "bypass mode", just like when the bypass is disconnected? Shouldn't I still see the timing light flash, even at the low speed of the starter cranking it?... unless pulling the bypass is effectively KILLING the spark?

That's where I was checking it at initially, but moved to drivers side to be closer to the dizzy (when I was spinning it). Spark from coil it bright blue and will jump several inches, but seems to loose a bit at the cap. However, with the bypass disconnected, it fired fired the first few revolutions, stopped, fired intermittently for a few more revolutions, and then just stopped.

I've attached the PDF wiring diagram I used for the wiring. Coil, A6 (ECM 12V), and Injectors are ALL tied together (under dash, near ECM) & powered directly off a relay (another OEM FP relay). As I reported earlier, I *had* the tach signal (mistakenly) grounded and wonder if this may have fried both the ECMs I have (both were tried/attached when tach signal was grounded)?... Since the injectors are being grounded (12V is constant, correct?) even when the engine is NOT rotating to get ignition pulse... seems they are being "back fed" by a bad component(s) or wiring issue?

Coil & EST (both GM takeoffs) pre-harness attachment. Closest connector wired to 12V/tach & far connector feeding EST using factory pigtail...


Post-harness...



Don't have any good pics of the dizzy, but... it's a standard Duraspark II with both vac & mech advances disabled (pickup coil does NOT move) with orange/purple wires feeding the EST (wired per the PDF)

dr.fiero

Although it won't kill it, one thing I'm seeing is your p/u coil wire running straight over the ignition coil! That close of a proximity might cause induction, and false pulses. Can you rotate the module 90* or something?

I'm thinking there has to be a wiring fault somewhere here though....
There 'should' be no way the injectors continue to fire after the engine stops rotating!

Caver Dave

Should be able to remove the bracket holding the EST to the coil bracket, add ground, and move it away from the coil...

I believe you're correct sir! Outside of splicing in a new IAC connector and 12V feeding the coil/A6/injectors (both hacked in the JY ), the harness itself wasn't cut. I did label (both ECM & component ends), hand trace, *AND* ring each wire before removing the un-wanted wires from the bundle...

RBob

iTrader: (1)

I would double check and possibly reset the pickup coil to reluctor gap. When I say reset that is to try a different gap if the current gap is correct.

The other item is the ignition module. From your description of the problem is sounds like it is bad. Try to find a GM module (even if in the JY) and try that. I'm a firm believer of using GM stuff whenever possible.

Also note that the MAP sensor should be mounted with the vacuum port facing down. With a downward slope of the vacuum/pressure line run to the manifold.

RBob.

Caver Dave

Just thought of something! Going back to when I had the tach signal grounded...

I also pulled the black ground wire from the dizzy (visible in the dizzy pic), over to that area, but don't recall *WHERE* I tied it into the harness! *IF* it's still tied into tach signal (white shown connected to dk.green wire to my tach)...

However, shouldn't it be killing the spark ALL the time, like when the coils tach lead was grounded?

Will definitely check it this evening just to eliminate that being the issue entirely, but feel I likely extended the wire & tied it back to ground (rather than into the harness). OTOH, at this point I'd LOVE to find it as "the cause"!

Caver Dave

I'm not sure there's any way to correct it RB. IOW, the coil is mounted to the plate with some type of rivets/capped studs...

I thought that before the booger was tested good 4 times on 2 different machines. But I've seen it happen before!

I was told (& read) that ... I'll move it once the timing issue has been sorted!

RFmaster

Caver Dave

Check your ignition coil - external coils like you have are prone to fail. Furthermore, by continuously having TACH lead grounded you have kept primary side of the coil energized at 100% duty cycle - pulling some serious current for an extended period of time, which it is not capable of handling (e.g. dissipating heat)! I am venturing on the limb, that you may have an intermittent coil - as it warms up the primary winding opens, killing spark.

RBob is correct to point out MAP sensor orientation, but that can be addressed rather easily.

Every time I go to JY I grab one or two EST modules, preferably GM.

To verify your magnetic pickup functionality you really need to have oscilloscope (i.e. to observe magnetic sensor output voltage). There is an excellent write up about EST operation on Megasquirt website under Megasquirt II, ignition, GM HEI:
http://www.megamanual.com/index.html
http://www.megamanual.com/ms2/heiest.gif

//RF

Caver Dave

Well, despite a long planned trip to the coast coming up tomorrow (nothings packed), I had to rush right home and putz with it further! Dizzy ground is independent and is grounded to back of the block, so that wasn't it...

Decided to physically MOVE the EST over in front of the TB, used a jumper (alligator clips) from heatsink to ground... and she fired up with the bypass DISCONNECTED!

Don't know whether it was the wires or the EST, but it appears being so close to the coil was the issue! I was able to set the base timing (disconnected still) at 10*BTDC, any less & it didn't want to idle at all. Revving with the jumper disconnected showed the timing run up to 20* (limp mode?). Locked it down, cut it off, connected the bypass, pulled the ECM fuse (5 mins) and fired her back up. Idle is at 27* and about 35* when rev'd to 2500, but settles back 5* after a second. Is this all acceptable?

Depending on how fast I can get everything ready & loaded tonight, I may see if I can set it a little lower. Starting (now that it's warm) requires a throttle bump... will it get better as it runs a bit (BLM blanked when fuse was pulled) or could the base 10* be too much?

I'm stubborn, so I want likely call this "fixed" until it continues to operate the same for a while! Maybe I'll get the MAP & EST remounted elsewhere and have time for some datalogging runs next week when I return?

RFmaster

EST is a current sink and requires a good ground!!! It is, after all, a high power switch that controls ignition coil current flowing through primary winding. Make sure to have a ground lead of at least 14 AWG size or better to a single point electrical ground lug - 3/8" stud or something appropriate.

Your timing is on the money - you'll have to do some data logging with WinALDL to determine commanded (after all corrections were dialed in by ECM). EST module by itself advances timing to 10 degrees so a total of 10+10 =20 appears to be reasonable. You'll have to edit BIN file and set base timing to 10 degrees to make all other things work. Enjoy good Friday tomorrow - we tackle this project when you ready.

//RF

jfwireless

I did the same TBI conversion to my 1976 Jeep CJ7 with a 304. Used the same ECM harness out of a 1989 CK1500 with a 350. Same 55 lb injectors. Had no trouble with timing at all. I had to set the base timing at 10A, and when I connect the bypass it advances to something over 20A. The first time I tried to start it up I had the magnetic pick up polarity reversed, and I had a bad EST. After that was fixed it ran great and had no hesitation at all. I did have an issue with my distributor causing some drop out and surging, but that ended up with a gear in the reluctor just touching the magnetic pick up, fixed that and all is well.

The intial fuel tables were really rich, so I did have a rich flag on intial start up. Added Bob's EBL Lockers flash board, ran some VE learns and the 304 runs great.

Also no need to run a ballast resistor or resistive wire as the EST has current limiting control as I understand it, so that gives a better spark, if Dave still has a ballast resistor in his harnness or resistive wire he should remove it, the Chevy TBI system never had a ballast resistor.

Idle range for a 304 is 600-800, after IAC set up I adjusted mine to 600, I am sure Dave has done the IAC set up. Idles great in either OL or CL, hot or cold.

The fact that Dave's injectors continue to fire after the engine stalls indicates a wiring/fault issue of some kind. The ECM fires the injectors, I can only assume, becasue I do not know that the ECM is looking for timing reference from the EST to determine if the engine is still running. If that is true there may be a wiring issue from the ECM to the EST, or a ground issue. I created a common point ground on top of my intake manifold to ground all my sensor/harness grounds to insure no ground loops or issues.

So his set up should work just fine with his 304 with no intial ECM changes to get up and running. I would expect he will have to tune his fuel tables as I did after the 304 is running correctly. The injectors firing after engine stall is the clue here I believe.

Jim

Dmity Kiev

O have the same problem my timing advance only 8 at all rpm , but i never seen 43 code. I replace all ingnition system components tree times , i put them from near worked car and almays got same problem NO TIMING ADVANCE , I replace ECM to stock L03 with stock bin and still have no advance. I even made new wire harness for ingnition system nothing helps. my ECMs is 6965 now i can patch it for knock test ? Im tired from this 2 month every day works with car ... can somebody help me ?

jfwireless

If you have the magnetic pick up coil wires in your distributor reversed you will not get any timing advance. Check the mag pick up wires.

I assume this is a junkyard TBI build, not a stock TBI . This thread is about an AMC 304 junkyard TBI install issue, If you have a stock factory TBI system you should start another thread and identify your car and engine.

Jim

Caver Dave

Thanks again Jim. After moving the EST/pickup leads, it advanced perfectly. Guessing Dr.F was right about some type of interference from the close proximity?? Unfortunately, I need a few more inches of length on the EST wires, so it appears I'll be cutting the (freshly) bundled & taped harness back open to pull some slack!

Oh yeah, she's got black exhaust & I've got burning eyes! I've been out-of-town for the past very warm & sunny weekends, only to have cold & rainy weekdays, but hoping for a reprieve later this week for some data logging... time to get 'er done!

Nope, while the ballast resistor *IS* still there (as good a place to stash it for a trail spare for another rig), it's been bypassed and I'm throwing a full 12V to the GM ignition.

jfwireless

Dave:

That's awesome glad that timing issue is fixed. Maybe run some shielded cable on that extended pick up lead, I used an MSD pick-up extention cable.

Been working on 360 to replace my 304. Have been talking to the camshaft vendors about a special grind for a TBI 360. EFI engines seem to like more lobe seperation and more vacuum than carbureted engines. As there never was an EFI 360 thought I woudl try and improve the burn and efficiency of the TBI 360. I think I will start a new thread here and ask about suggested Camshaft specifications for the 360 to check out what the camshaft vendors are sending me. Of course I am looking for lots of low end and mid range torque.

jfwireless

Dave:

That's awesome!! glad that timing issue is fixed. Maybe run some shielded cable on that extended pick up lead, I used an MSD pick-up extention cable used with the 6AL ignition box as I have an MSD Billet distributor.

Been working on rebuilding an AMC 360 to replace my 304. Have been talking to the camshaft vendors about a special grind for a TBI 360. EFI engines seem to like more lobe seperation and more vacuum than carbureted engines. As there never was an EFI 360 thought I would try and improve the burn and efficiency of the TBI 360. I think I will start a new thread here and ask about suggested Camshaft specifications for the 360 to check out what the camshaft vendors are sending me. Of course I am looking for lots of low end and mid range torque. Do not need anything over 5500 rpms, and with EFI a good idle. Looks like a mild HP gain of some 30 HP. I will go with a CR of at least 9 versus the stock 8.25.

Jim

Caver Dave

I'm glad too! I forgot to mention that I'd twisted the leads already (strictly to take up some of the slack), but was going to look into shielding them somehow to see if that would resolve the interference WITHOUT having to rework everything!

Tonight, I plan to re-visit the twists to insure it's twisted completely end-to-end and try some AL tape (appears to be either HVAC or flashing related) to see if it will make a difference... unless anyone has a better method/idea?


Have you been able to find the correct flexplate for a 360/AMC cased TH-400? Or were you gonna have the 304 flexplate rebalanced?

dr.fiero

I've been using some wire that has a simple 2 conductor with a built in shield for doing a lot of my sensors. Since the current you're dealing with is pretty low, you could probably use good quality headphone wire since it usually had the foil ground built in!

Remember to only ground ONE end though or it negates the effect!

Caver Dave

Would covering the leads with a section of flexiible metal conduit work as a shield (provided 1 end is grounded)? Or should I stay with the AL foil tape?

RFmaster

Dave

Headphone cable does not have temperature range - as it is made using cheap grade plastic jacket. Under hood temperatures can be easily in excess of 120C and consequently such cable installation will fail over time. I would look for high temperature PTFE based coaxial cable such RG316/U or RG174. These cables are available as mil spec cables, have 90+% shielding and were designed to handle temperature extremes up to 200C.

//RF

jfwireless

?

Yes, I found a 360 flexplate, a good price also.

I went and looked at my MSD distributor pick up extention cable , it is not a shielded wire, and mine is at least 3 foot long as I have the EST mounted in a mini-box on the passenger side firewall to keep it running cooler. The wire runs in the loom with all the other cables with no apparent interference. But I am using an MSD Billet Distributor (8519) with a very large magnetic pick-up, most likely putting out more energy than your Duraspark.

I think your EST and pick-up cable is mounted to close to your coil, that is what the issue is.

Jim

Caver Dave

My apologies for the long delay in updating. Much on the plate and unfortunately it hasn't been with TBI...

Anyway, caught a few minutes this evening to test some shielding techniques.

I pulled the dizzy leads between the DS & EST... only to find they weren't as twisted as I recall! However, was able to get about 15 twists into the leads. The length was then wrapped with some strips of AL tape (appears to be either HVAC or flashing related). I started with a 50% overlap that gave a double wrap and double wrapped it for 8" from the EST end. I also sanded the mating surface between the coils OEM bracket & the bracket made to hold the EST and treated it to small amount of no-lox (grease) to insure the EST was getting a good ground. The EST was was remounted angling up from the coil, "shield" was grounded, leads were connected, and draped well shy of the coil.

I fired her up to insure everything was good before disconnecting the bypass. Shut it off, pulled the bypass and she fired back up! A quick check of the timing showed an advance of 10*. I loosened the clamp and was able to bring it back to 2*-3* BTDC. Checked it again with the bypass connected and found it at 15* with spikes up to 20* as rpm increase.

This appears to show the meager attempt to shield the leads worked, correct?

Comments?

RFmaster

Dave

Looks like timing is working correctly... Do not forget to disconnect battery to clear that code 42 after setting timing (EST plug should be reconnected). Fuel is next (350 ASDU with 63 lb-hr injectors on 304)? I would try to locate 5.0L 55lb-hr injectors. These may make your idle better (commanded injector duration time at idle will be long enough), but first do some data logging and see what your CL BLM's look like.

//RF

Caver Dave

I was planning to pull the ECM fuse for an hour or so once I get home this evening to mow. Seems even the lawn is out to pile on when I'm busy!

I'd thought of dropping a set of 5.0 injectors in , but... IMO the 5.7 injectors should be more plentiful in the JY & at the parts houses in the podunk villes around offroading venues. Plus, I already have 3 sets (2 loaded in spare TBs)...

The current chip is ARPC [305 truck manual] with the EGR "on temp" (supposedly) raised up to disable it. Not sure if anything would be effected like the VSS, which aside from the EGR, is the only other component I'm not running.

Earlier logging with both ASDU & ARPC showed extremely rich conditions. Not sure if getting the timing functional will do anything for the richness, but I hope to get some logging runs later this week/weekend.

jfwireless

I am running the 5.7 injectors in my 304, no problem after adjusting the BPC and fuel tables. Running 13 lbs of fuel pressure. I did start out with a BC of AJUK which
is a 5.0 with auto before I added the EBL Lockers flash board. A better choice than the ASDU. My 304 ran OK with the AJUK BC, just a lttle rich.

Jim

Caver Dave

I was able to take it out Friday night for 15 minutes with no TBI related issues, but the Rancho 9000s dialed-up almost beat me to death. At some point, the VSS threw a flag (Err24), the SES came on (at least that's working!) and followed at some point by the ESC (Err43, which is where I was at when I found the "no SA"). Unfortunately, I couldn't get a rider and at some point while laying a hand on the laptop to insure it didn't fall out, stopped the data capture. Decided to take care of a few minor issues and pulled the fuse to clear the codes in prep for Sat's run.

Despite a long chore list and son's impending first prom , I was able to make a 30 minute logging run yesterday. Figuring the ESC/43 would resurface, I drove around normally with a few WOT take offs on even ground (stop signs/lights). VSS flag popped about 10-15 minutes in and just needs to be pulled in the bin.
As I suspected, the ESC/43 code stayed away the entire trip until intentionally pulling a 40* hill on the way back to the house (intentional since IIRC, after the 43 code is thrown, the ECM would go into limp on the timing?). There appear to be NO knock counts prior to where I was running 50-55mph and went WOT near the base (thrown around time 1571sec/26min).

Not sure how that figures into the 43, but it seems to throw ONLY WHEN there's a steep grade at WOT? I believe if I stay away from the grade & WOT, it wouldn't come back in 100 miles worth of logging. Outside of that, everything appears to be fine... other than chronic richness, correct?

Anyways, the data...

RFmaster

Dave

Congratulations on your first run! Based on your data log file:

1) VSS - Your ECM is not receiving VSS pulses. There is no VSS data in log (0).

2) Code 43 - this is requires a bit of digging. IRC, a loss of knock sensor output signal or loss of ground at the ESC module will cause the signal at the ECM B7 to remains high. ECM has a self check routine to verify KS/ESC functionality as a part of its control logic. Code 43 is checked whenever the engine is first started, and the ECM checks the function of the ESC module. Once engine operating temperature is reached and the throttle is opened above set point( also above 1500 RPM), the ECM will advance the timing until KS detects pinging then back off the timing. If the ECM does not detect the KS operating, it will also set a code 43. There were no knocks detected in your data log! Code 43 set when:

• Voltage at Knock Sensor is above 4.8 volts or below .64 volts.
• Either condition is met for about 10 seconds.

Possible causes:
1) Open or shorted knock sensor
2) Loose knock sensor
3) Excessive mechanical noise within engine


//RF

Caver Dave

Thanks RFM! I've logged a few times previously running 5.7 bins, but this is the first with the 5.0 bin. I'd hoped it would alleviate some of the richness, but the logs still show it massively rich!


Yes, appears I need to speak with my "chip burning buddy", since he knows I'm not running a VSS

*That's* what has me confused! The code *ONLY* appears to manifest on that specific steep hill *AND* WOT... The prior 26 minutes of "normal" driving that included several WOT runs from the lights (playing with some young ricers ) and that same hill under steady throttle. I've searched for plausible reasons like loose wires going open with engine torque, etc. without anything any success...

1) Well, a quick check after arriving home yesterday after the run showed the KS (PN "DR699 6148" stamped on it, but have no idea *which* donor it came from) at 100K ohms to itself and the block. Same today (engine cold)
2) I was able to spin it out by hand... too loose?
3) Well, it *IS* an AMC... their not exactly known for "sewing machine" operation

RFmaster

Dave

HMMM hill = knock (anything is possible....)

Take a look at your ESC module and record its part number.

For non roller, flat tappet cams I would use GM P/N 1997562, 1997699, 10456017,10456287; Delco 213-325; Wells SU121; SMP KS45, KS46, KS49, or KS117 have a design frequency around 5.2 kHz. No two KS sensors are the same due to build differences.

For ESC module look for GM P/N 16022621, 16052401 to name a few.

The ESC module sends a voltage signal (8 to 10 volts) when NO knock is detected by the knock sensor. If knock occurs, this signal is pulled low. Duration of low voltage condition causes ECM to command amount of timing retard.

//RF

Caver Dave

The ESC# is 16052401 8184... thinking back on this, could it be caused by a mismatch between the ESC (known to be from '89 2500 5.7L) and the KS (have no clue...could have come from the bucket of 4.3L parts we grabbed for my brothers AMC 4.2L I-6)? IOW, the ESC is looking for a specific frequency/voltage from the KS and if they are not jiving due to coming from different systems...

jfwireless

Dave:

I used a matched pair ESC/KS out of a 305 as the 305 was close to the 304 in size and was also a small block like the 305. I never have seen a single ESC/KS error code, but neither have I seen a spark knock count at all. It was my understanding certain KS work with certain ESC's, so that is why I picked a set at the parts yard. After reading RFmasters responses I am going to insure my ESC is enabled in the bin. I also have the KS installed in a water jacket drain plug in the AMC block, but I had to use an adaptor as the drain plug hole was smaller than the thread on the KS. I am going to try two things on the 360 build, first try and turn down the threaded end on the KS and tap it to fit the waterjacket drain plug hole, or as recommended by a local performance engine builder weld a length of threaded rod to the end of the KS to install in the water jacket hole. Apparently he has done this with success in the past on TBI conversions. I prefer to try and turn down the treaded end of the KS if the threaded end is a solid piece of metal.

Jim

Caver Dave

The KS I'm using fit's the block threads just fine.

After checking resistance yesterday, I looked for another KS for comparison... NONE in either the 5.7 parts bucket (mine) or the 4.3 bucket (for brothers 4.2 I6). I *KNOW* I personally pulled the 4.3L and the KS on the first 5.7L donor was busted. While I do recall pulling additional 5.7 KS's for spares, I can't lay my hands on them... This really makes me suspect it may be from a 4.3!

jfwireless

Dave:

I measured the resistance of my KS to ground today, it was 8.2K ohms. The KS is basically a narrow band microphone, so I do not know what the resistance really means here. As I recall a KS is a piezio device(crystal) that resonates at a pre-determined frequency. As crystals have a very high Q(very selective) they can hear only certain precise frequencies.



Jim

Jim

Caver Dave

Searching found this ditty...
A show of hands from those thinking I have a late(r) model KS?

RFmaster

Daaaa! Comrade!

RBob

iTrader: (1)

The 100K ohm knock sensor is the correct one for your ECM.

The 16052401 knock filter is HKR which was used on 4.3l and 5.7l engines in cars, trucks and vans. (4" bore).

RBob.

RFmaster

Agree
The part numbers I have listed were from 350 CID list of parts - sorry. IRC AMC 304 has 3.75"x3.44" bore x stroke compared to SBC 305 3.736" x 3.48" bore x stroke.

305 specific KS 1997562 used on just about all 5.0L 80's cars (and matching ESC module) should do the trick.

//RF