The Rodding Roundtable
Motorhead Message Central => Rodder's Roundtable => Topic started by: 40_Tudor on October 02, 2014, 05:32:47 PM
My 40 Tudor with 87 IROC 5.0 TPI would not start the other day. Check.. no spark. 12 V to coil and distributor control module. Pulled cap, contacts on pickup coil was green. No resistance on ohm meter. Got new pickup coil, Jeg's Excel module and coil. Set timing @ 6 deg with brown wire disconnected.
It runs but * when accelerating and misses above idle. Code 33 at ALDL. No vacuum leaks to be found.
This has been converted from a MAF to a MAP sensor when I built it over 5 years ago.
Ran fine before pickup coil went out.
Any suggestions?
Check with this chart http://chevythunder.com/maf_code_33.htm It's a MAP sensor code, my guess you have a broken or disconnected vacuum line.
Quote from: "40_Tudor"My 40 Tudor with 87 IROC 5.0 TPI would not start the other day. Check.. no spark. 12 V to coil and distributor control module. Pulled cap, contacts on pickup coil was green. No resistance on ohm meter. Got new pickup coil,
Ran fine before pickup coil went out.
Any suggestions?
pull the cap and rotor back off... use a bright flashlight to look down at the top of the reluctor on the small cap HEI shaft...
see if its cracked like this..
(http://i1207.photobucket.com/albums/bb476/waynep712/smallcapheicracks.jpg)
why would this effect anything..
so we have a cracked magnet on the signal generator armature..
~~~~~~~^~~~~~~~^~~~~~~~^... so it creates a random or ghost waveform in the pickup coil.. below 400 RPM the electronic spark control is NOT active.. above and with the tan wire connected it is..
disconnect the tan wire again.. see if the engine runs better.. i know what a chore removing the cap and rotor is on a TPI motor.
electronic spark time when engaged looks at the AC wave form.. and instead of opening the power transistor as the tips of the reluctor align with the tips of the pickup coil it keeps a timer going.. shorting the delay from the pickup coil passing zero going negative event.. to open the power transistor to trigger the coil...
if it shortens the delay.. it advances the timing..
if it lengthens the delay.. it retards the timing..
the ghost patterns in the wave form trigger random count downs and out of phase spark events. .this causes weird running of motors..
please also examine the sides of the ignition coil...
(http://i1207.photobucket.com/albums/bb476/waynep712/waynep712%20carb%20album/gm%20TBI/dbbc7910-b2b1-4009-9900-9e95cda84a7b_zpsb8436a2a.jpg)
this has most of the info you may need..
http://forums.superchevy.com/corvette-fever/70/8585187/c4-corvettes/which-used-scan-tools-for-82-to-94-corvettes-with/
Thanks for the tips Wayne and Enjenjo. I'll do some checking this weekend and let you know what I find.
I need to find an older OTC scanner for my OBD I ALDL.
Hey Darryl when I was over your way last year I bought a INNOVA OBD1 scanner for my 5.0L EFI 34Coupe I also bought over there as we don't have then here in OZ.
It proved invaluable in diagnosing my engine problems. However while using it a little while later the engine stalled while carrying out an KOEO test damaging the scanner. The screen now flashes on and off continuously rendering it useless.
I hope you have better luck if you buy one.
Quote from: "bucketmouth"Hey Darryl when I was over your way last year I bought a INNOVA OBD1 scanner for my 5.0L EFI 34Coupe I also bought over there as we don't have then here in OZ.
It proved invaluable in diagnosing my engine problems. However while using it a little while later the engine stalled while carrying out an KOEO test damaging the scanner. The screen now flashes on and off continuously rendering it useless.
I hope you have better luck if you buy one.
innova will fix those usually... would you like contact info..
http://www.innova.com/
http://www.innova.com/en-US/support/ProductSupport
is this the version you bought for ford EECIV
http://www.innova.com/en-US/Product/Detail/0b8de87a-0bfd-4bae-aed5-4eac63c4a0a4
i had a similar thing happen to my autoxray.. but the wiring harness was shorted out and the owner turned on the key to roll up the windows when i ask him to come out and disconnect the battery.. as i had my fingers separating the wiring in the harness.. i ended up opening and just carefully resoldering my unit.. and it works again..
please print and perform this test on your ford before you plug any scan tool back in.. and since its eeciv. look at the harness near the computer connector.. you will find that there is a pair of wires sticking out with ring terminals.. those must be properly grounded to the body.. and the engine properly grounded to the body as is proved on test #4
http://i.imgur.com/WMDprhm.jpg
you can actually use an analog volt meter.. one with a needle to read ford codes.. this is me getting codes out of an 83 cressida with it.. and the reason you need an analog volt meter.. as the space between the numbers is 2 volts or so... its impossible to view the pulses and figure out what they mean with a digital volt meter.. i know i tried..
Update on code 33 problem.
Checked distributor magnet for cracks, looks good. New Eccel coil and dis. control module. Put old GM coil back in, not difference. Idles OK, runs fast OK, normal starting out...not so good.
Tested MAP sensor voltage, 5v going in, 5v out on center lead. Went to store and picked up a vacuum pump. Test lead on center lead, 5 volts no matter what pressure is. Pumped down to almost 0 and still had 5v. Going to pick up an Echlin 1 bar MAP sensor this weekend.
This should be fun.
Guy behind counter. What year and model car do you have sir?
Me...1940 Ford.
Him... My computer doesn't go back that far. I didn't know they had MAP sensors back then.
Me... Well the motors out of a 87 Iroc.
Him.. Well that has a MAF sensor
Me... Not any more.
I found 1 guy down here that speaks hotrod but its at AutoZone and I'm not going to put in Taiwan ignition parts.
Supposed to rain for the next week down here so not sure when I'll get to drive it. Not very water tight yet.
Quote from: "40_Tudor"Update on code 33 problem. Tested MAP sensor voltage, 5v going in, 5v out on center lead. Went to store and picked up a vacuum pump. Test lead on center lead, 5 volts no matter what pressure is. Pumped down to almost 0 and still had 5v. Going to pick up an Echlin 1 bar MAP sensor this weekend.
check grounds...
pin C wire to pin A wire should have 5 volts..
Pin C wire to pin B wire should vary..
pin A to B should also vary in the other direction from C to B.
PIN A wire to the negative battery post with the key on should be really close to 0.00.. but NOT exactly ZERO.. flip meter to 2 volts DC and you should see a fraction of a volt.. 0.02 or so.. i worry that you have lost the ground.. no ground and you will get only 5 volts out of everything..
(http://i1207.photobucket.com/albums/bb476/waynep712/corvette%20diagrams/gm_map_sensorwiring_zpsae626eb2.jpg)
if you loose the ground.. there is 5 volts all the way across the resistor in the map sensor..
with a ground. you have 5 volts on one end.. and almost zero at the other.. so the variable wiper.. can select how much to send back.. this is a solid state unit but it works very much the same way.
there are two or more individual ground connections.. to the computer.. they must ALL BE PROPERLY hooked up to ground on the engine block/heads
sample.. these are from a vortec astro van
http://i1207.photobucket.com/albums/bb476/waynep712/waynep712%20carb%20album/gm%20TBI/CAM00506_zps776ccec1.jpg
http://i1207.photobucket.com/albums/bb476/waynep712/waynep712%20carb%20album/gm%20TBI/CAM00505_zps8ee7b05a.jpg
http://i1207.photobucket.com/albums/bb476/waynep712/corvette%20diagrams/85TPIvoltagepinout_zps9b30f316.jpg
http://i1207.photobucket.com/albums/bb476/waynep712/corvette%20diagrams/86turbobuickECMpinout_zps4c3c64ec.jpg
i am not sure if these last two are the proper connectors for your computer. they are close..
you can see how the ground and power wiring are shared on some models this is for a LT1 version slightly later.. look at the lower left corner..
http://i1207.photobucket.com/albums/bb476/waynep712/corvette%20diagrams/92_95_C4_VIN_P_enginecontrolwiring_zps4926633d.jpg
in the lower left corner and in the upper center. B is actually ground.. and what is confusing is with the air temp sensor and the engine coolant temp sensor.. the other wire is 5 volts.. the variable thermistor varies the connection to the GROUND WIRE for the 5 volts. the computer has a Current limiting device on the 5 volt regulator for that circuit.. and it looks at how much voltage is NOT sent to ground to use for the calculations.. way different.. kinda a twist on voltage drop.. very creative.. and it works really well.. if you unplug the sensor. the voltage goes to 5 volts and the computer things the temp is -20F..
can you PM me with which craigslist you use.. there are several in ohio..
http://www.craigslist.org/about/sites
Quote from: "40_Tudor"
This should be fun.
Guy behind counter. What year and model car do you have sir?
Me...1940 Ford.
Him... My computer doesn't go back that far. I didn't know they had MAP sensors back then.
Me... Well the motors out of a 87 Iroc.
Him.. Well that has a MAF sensor
Me... Not any more.
I found 1 guy down here that speaks hotrod but its at AutoZone and I'm not going to put in Taiwan ignition parts.
you really need to have one of the eye glass cameras on when doing this..
or the cell phone in your shirt pocket turned on and aiming out over the lip of the pocket when you go in and ask for parts..
hint.. look up parts online by fuel injection application.. then ask for them by number ..
this helps sometimes in parts look up.. as some of the duralast stuff is wells
http://www.wellsve.com/parts/
i ask if the local autozone had any bags of oil absorbent when a oil filter became the exxon valdez in a friends driveway. the Autozoner kept asking what weight oil i wanted.. i keep saying i don't know.. it comes in a big paper bag.. i even said cat litter like stuff.. he told me to go to the grocery store. you should have seen his face when i walked in grabbed a bag from the display in the front window and dropped it on the cash register counter in front of him.. he had never seen or sold that.. did not know what it was or what it was for.. at least all the out door cats did not run up and roll in it like happened last time i poured out a big bag of it on a 50 foot oil streak from a blown filter. .
Wayne,
I'll double check the readings this weekend before I go to the parts store. I checked the grounds the other day, never hearts to check them again.
The shop I used to work in we had several test MAP sensors we used just to test the circuit. Wish I had one now.
I have a home in Columbus Ohio but I'm working a contract job in Lexington, KY making technical manuals for military ground vehicles. I do the exploded views for the manuals.
I've never use Crags list or face book.
I'll let you know what I find out this weekend.
Quote from: "40_Tudor"Wayne,
I'll double check the readings this weekend before I go to the parts store. I checked the grounds the other day, never hearts to check them again.
The shop I used to work in we had several test MAP sensors we used just to test the circuit. Wish I had one now.
I have a home in Columbus Ohio but I'm working a contract job in Lexington, KY making technical manuals for military ground vehicles. I do the exploded views for the manuals.
I've never use Crags list or face book.
I'll let you know what I find out this weekend.
this looks like it might have the right stuff.. its 150 bucks but it will also do a lot of import cars.. or ebay the extra stuff..
http://louisville.craigslist.org/ele/4657226005.html
Wayne,
I rechecked the streetrod today with your cheat sheet.
Here's what I got:
Key on, test probes in connector with MAP connected. Meter set to 20v
A to B = 0.56v
A to C = 0.10v
C to B = 0.67v
Vacuum applied "no change"
Key on: A to engine ground = 4.90v
Key off: A to engine ground = 0.000v "varies a little if I tap meter or probe ~ 0.006
A to ECM plug, MAP disconnected ECM plug disconnected, (ground wire MAP plug end to ECM end of wire = 7.65 ohm. Key off Checking continuity between plug on MAP and ECM. Same reading no matter where I ground second probe from MAP plug to ground.
change map sensor..
did you see this interesting write up over at wells
http://www.wellsve.com/ds_map.html
won't help you diagnose your issue..
for a 90 camaro 5.7
http://www.wellsve.com/parts/index.php?PART_KEY=000663767&PART_NO=SU105
http://www.wellsve.com/custom_searches/showpinoutdiagram.php?partno=SU105#zoom=100
ahh.. this is what i was looking for..
http://www.wellsve.com/custom_searches/pdf/sales_drawings/SU105.PDF
it shows the voltage verses vacuum output..
just to save you some calculations if your vacuum gauge is not marked with both calibrations..
20KPA is about 6 inches of mercury
55KPA is about 16.25 inches of mercury
85KPA is 25.1 inches of mercury.
wow... and what a win by baylor..
I rechecked all of the grounds, put an extra ground on ECM case to body, still no change in readings when vacuum is applied. The MAP sensor was used one we had in the cabinet at the shop I used to work at. I think I'll pick a new one at NAPA and see if the readings are any different. I need to check on that OTC you sent the link for too. If I where back home I could go into the shop and barrow the one they have. 250 miles away presents problems.
More updates to follow.
Joe
Put in an new MAP sensor and it still runs bad, maybe worse.
Pulled dist. cap back off, got bright light, magnifying glass and found some small cracks in the magnet around the shaft.
Going back home this weekend I'll stop in to the shop and see if I can find another distributor and try it. One with out cracks.
the cardone Reman distributors have a completely different reluctor
this is a V6 distributor reman by cardone.. the V8 versions are similar but with more pole pieces ..
(http://i1207.photobucket.com/albums/bb476/waynep712/4pointthreeTBIdistributer.jpg)
hint.. before you take the distributor out... slip the rotor back on it..
bump the engine around till the rotor is pointing toward the #1 wire position..
pull the rotor if you cannot see past it.. and perhaps with a friend.. turn the crank in normal direction of rotation until the reluctor poles line up perfectly with the pickup coil pieces.. look down at the timing marks.. see where the damper mark lines up with the pointer on the timing cover.. you can now.. remove the distributor.. install a new one.. get the rotor pointing in the proper position.. verify the distributor has dropped onto the oil pump shaft..
you can if you have to with the distributor almost fully installed.. bump the engine around two more turns at the crank.. this should bring the distributor back to the exact same spot.. align teh damper either to your previous setting or to base timing..
turn the housing to align the pickup coil poles with the reluctor poles. and lock the distributor down.. you are now ready to install the rotor , cap.. wiring.. and it should start and be so close to perfect..
i am just waiting till i get the next small block chevy on the stand so i can get somebody to video tape this for you tube.. i can perform this so fast its crazy.. i loved working in shops.. i would say.. oh.. i have to take the distributor out to work on it.. what i did not say is that i preset the engine and distributor.. so i could yank it out and know exactly where #1 is when i go to reinstall it.. when i drop it back in.. i then lock it down and reach thru the window.. turn the key and it fires up on the first try.. blowing everybody away.. i would just answer them.. why do you think they hired me..
The guy I used to work for taught me to do it that way too.
He started the business in 1946. I started working there in high school and went back on and off, between jobs and collage. He probably forgot more that I'll ever know about working on cars. He's gone now but the guy that took my job when I left, about 30 years ago bought the place a few years ago. He still lets me take my cars in to work n them there.
I called him this morning and he has a use distributor I can have to try.
I'll put this one in and if that solves the problem I'll look for a new one at one of the car shows.
Any recommendations, Accel, MSD?
More updates later.
Quote from: "40_Tudor"The guy I used to work for taught me to do it that way too.
He started the business in 1946. I started working there in high school and went back on and off, between jobs and collage. He probably forgot more that I'll ever know about working on cars. He's gone now but the guy that took my job when I left, about 30 years ago bought the place a few years ago. He still lets me take my cars in to work n them there.
I called him this morning and he has a use distributor I can have to try.
I'll put this one in and if that solves the problem I'll look for a new one at one of the car shows.
Any recommendations, Accel, MSD?
More updates later.
i have tried Neither in an L98... probably the MSD would be better.. easier for parts..
mostly i find the remans with a lifetime warrantee for a bill plus with the improved reluctor design work great.. nice clean sine wave output from the pickup coil..
i am glad i am not the only one to know that trick.. i do try to share is when i can..
I used the Cardone reman on my TPI per Waynes recommendation and it was a major improvement. 20,000 miles with no problems.
Thanks for the recommendation Okiedokie.
Always better to find someone that's used a brand and got good results. I'm going to try the used one from my old shop to make sure I have missed something else before I buy one. Pick it up Friday then put it in the first of the week.
More updates later.
If you live close to an Advance Auto parts store, look up their online coupons and order online then pick up at the store, save up to 30%. Do a search.
Finally found the code 33 MAP sensor problem.
Mechanic at work brought his OBDI Snap-On scanner so I could use it. Problem is you have to have a vin to get it to run. None I tried would work. Finally ran a jumper from ECM to ground on MAP sensor, "like Wayne suggested in the first place" and cleared the codes and started it up, no codes. I was running another ground wire out through the file wall and had to cut some of the zip ties off the wire bundle way up under the dash to add the new wire when I found the old MAP ground cut by a sharp edge on a zip tie.
I'm going to check all my inventory of zip ties and through out any with a sharp edge. You wouldn't think a piece of plastic would cut wire but id did.
Fixed the problem now its snowing so I cant drive it anyway. Bumber.
glad you were able to find the problem..
decades ago.. an 81 camaro.. computer control.. critters ate into the engine control harness.. i had to cut and splice it.. but even though i had been to GM tech classes.. i was NOT aware how easy the harness was to get out..
i was there with a beckman multimeter probing each wire looking for continuity and looking for shorts to ground.. i had been looking for this last short to ground for about 2 hours... continuity beeper going on constantly.. i had everything on both sides of the firewall disconnected.. the boss said. close it up for the night.. i did not want to loose where i was hooked to so i pulled the wires from the face of my meter.. it was still beeping without any test leads plugged in.. DOH!!!!!!
Thanks for following up on the problem. This will go into my TPI file.
glad you found the problem. Grounds are often over looked... in this case it was a hidden fault. I would not think a plastic pull tie would cut a wire. Something to keep in mind
For decades I have said : "The simple S**t will get you"
Who would have thought a zip tie would do that it's something else to keep in mind for future reference.
For those of us not to clued up on electrical diagnosis we tend to over look earthing problems because we think it's something more sinister.
I got caught out earlier this year with my coupe and it was as simple as fitting an earth strap and a new earth wire.
Glad you got it sorted and too bad about the snow. It's the start of summer here the weather is starting to warm up.